Biomedical subjects

A Ferret

Publications and source records attributed to A Ferret.

18 recordsLinked to original sources

PubMed2006

Analysis of litter size and days to lambing in the Ripollesa ewe. II. Estimation of variance components and response to phenotypic selection on litter size.

A performance data set from 376 Ripollesa purebred ewes of the experimental flock of the Universitat Autònoma of Barcelona was analyzed using a bivariate Bayesian threshold-linear model. The data set contained 1,598 litter size records and 1,699 days-to-lambing records. The model included the additive genetic effect of each animal and 3 nongenetic sources of variation: ewe age, year of lambing, and the permanent environmental effect characterized by the ewe. The flock was phenotypically selected for litter size since 1986, and replacement ewes and rams were selected from the progeny of the more prolific ewes, which had at least 3 deliveries recorded. The phenotypic trend for litter size was positive, whereas days to lambing followed an unclear pattern. Both traits had low heritabilities; 0.13 for litter size and 0.11 for days to lambing. Response to selection was evaluated through (a) the average breeding value of the ewe lambs chosen annually, and (b) the average breeding value of the overall flock. The first measurement suggested a positive trend for litter size, although it showed important oscillations. On the other hand, the average breeding value for the overall flock showed a stable positive tendency after yr 4 of selection, with estimates clearly different from zero after yr 11 of selection. A significant increase in the incidence of multiple births was observed, with a mode of approximately 10%. The correlated response in days to lambing did not show a significant trend. The effect of year of lambing also positively influenced both litter size and days to lambing, although important oscillations were observed between years. Results indicated that litter size in sheep can be effectively improved through phenotypic selection, even in small flocks; moreover, days to lambing could also be genetically improved, given the estimate obtained for its heritability.

Animals↗

PubMed2006

Analysis of litter size and days to lambing in the Ripollesa ewe. I. Comparison of models with linear and threshold approaches.

The analysis focused on model fitting of 2 ewe reproductive traits, litter size, and days to lambing (interval between the introduction of the ram into the flock and the subsequent parturition of the ewes). The experimental data set of the Universitat Autònoma of Barcelona flock was used, including 1,598 records of litter size and 1,699 records of days to lambing from 376 Ripollesa ewes between 1986 and 2005. Univariate and bivariate models were considered as beginning points with linear or threshold approximation for litter size. Model fitting was evaluated in terms of goodness-of-fit and predictive ability, using the mean square error and the correlation between phenotypic and predicted records (rho(y,ŷ)) as reference parameters. The bivariate model was preferable for both variables, minimizing mean square error and maximizing rho(y,ŷ). A threshold approximation for litter size was preferable over a linear approximation. Models were also compared with a simulation study, comparing the correlation coefficient between simulated and predicted breeding values (rho(a,â)). The bivariate threshold model was favored, with a rho(y,ŷ) of 0.677 and 0.834 for litter size and days to lambing, respectively. Correlation coefficients between simulated and predicted breeding values in the bivariate linear model were reduced slightly to 0.651 and 0.831, respectively, and they were lowest with linear univariate models (0.642 and 0.802). Although the bivariate models for ewe litter size and days to lambing were more accurate than the univariate models, the threshold approaches showed a greater advantage under the bivariate model. For the purpose of genetic evaluation of litter size in sheep, use of the threshold-linear model seems justified. In the Ripollesa breed, the evaluation of litter size can benefit from recording birth weight.

Animals↗

PubMed2006

Effects of nonstructural carbohydrates and protein sources on intake, apparent total tract digestibility, and ruminal metabolism in vivo and in vitro with high-concentrate beef cattle diets.

To investigate the effects of synchronizing nonstructural carbohydrate (NSC) and protein degradation on intake and rumen microbial fermentation, four ruminally fistulated Holstein heifers (BW = 132.3 +/- 1.61 kg) fed high-concentrate diets were assigned to a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments studied in vivo and in vitro with a dual-flow continuous culture system. Two NSC sources (barley and corn) and 2 protein sources [soybean meal (SBM) and sunflower meal (SFM)] differing in their rate and extent of ruminal degradation were combined resulting in a synchronized rapid fermentation diet (barley-SFM), a synchronized slow fermentation diet (corn-SBM), and 2 unsynchronized diets with a rapidly and a slowly fermenting component (barley-SBM, and corn-SFM). In vitro, the fermentation profile was studied at a constant pH of 6.2, and at a variable pH with 12 h at pH 6.4 and 12 h at pH 5.8. Synchronization tended to result in greater true OM digestion (P = 0.072), VFA concentration (P = 0.067), and microbial N flow (P = 0.092) in vitro, but had no effects on in vivo fermentation pattern or on apparent total tract digestibility. The NSC source affected the efficiency of microbial protein synthesis in vitro, tending to be greater (P = 0.07) for barley-based diets, and in vivo, the NSC source tended to affect intake. Dry matter and OM intake tended to be greater (P > or = 0.06) for corn- than barley-based diets. Ammonia N concentration was lower in vitro (P = 0.006) and tended to be lower in vivo (P = 0.07) for corn- than barley-based diets. In vitro, pH could be reduced from 6.4 to 5.8 for 12 h/d without any effect on ruminal fermentation or microbial protein synthesis. In summary, ruminal synchronization seemed to have positive effects on in vitro fermentation, but in vivo recycling of endogenous N or intake differences could compensate for these effects.

Animal Feed↗

PubMed2006

Effects of dietary nonstructural carbohydrates and protein sources on feeding behavior of tethered heifers fed high-concentrate diets.

To describe the feeding behavior of growing heifers fed high-concentrate diets with different sources of protein and nonstructural carbohydrates, and to explain the ruminal fermentation pattern, 4 ruminally fistulated Holstein heifers (BW = 132.3 +/- 1.61 kg) were assigned to a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments. Two non-structural carbohydrate sources (barley and corn) and 2 protein sources [soybean meal (SBM) and sunflower meal (SFM)] that differ in their rate and extent of ruminal degradation were combined, resulting in a synchronized, rapid fermentation diet (barley-SFM), a synchronized, slow fermentation diet (corn-SBM), and 2 unsynchronized diets consisting of a rapidly and a slowly fermenting component (barley-SBM and corn-SFM). The corn-SFM diet resulted in a lower frequency of feeding (P < or = 0.05), longer meal length (P < or = 0.043), and larger meal size (P < or = 0.037) than the other 3 diets. Dietary treatment had no effect (P > or = 0.09) on the daily percentages of posture and behaviors. In general, heifers spent 9.97 +/- 0.83% of the day eating, 2.11 +/- 0.42% drinking, 25.13 +/- 1.36% ruminating, 16.97 +/- 1.42% in other activities such as social behavior and self-grooming, and the rest of the day (45.82 +/- 2.55%) resting or doing no chewing activities. Eating, drinking, and social behaviors were performed while standing (P < or = 0.01), whereas resting and ruminating occurred mainly while lying (P = 0.001). Eating took place mainly in the first 4 h after feeding (P = 0.001), whereas ruminating occurred mainly at night (P = 0.001). When chewing activities (eating and ruminating) were expressed per kilogram of DM or NDF from roughage intake, more time (P = 0.004) was spent chewing per kilogram of DMI for barley-based diets, and per kilogram of NDF from roughage intake for barley- (P = 0.01) and SFM- (P = 0.002) based diets. Tethered heifers fed the more fermentable and rapidly synchronized diet (barley-SFM) reduced intake and increased chewing time. With these high-concentrate diets, time spent chewing was inversely related to roughage intake.

Animal Feed↗

PubMed2006

Technical note: a modified three-step in vitro procedure to determine intestinal digestion of proteins.

An in vitro, batch incubator (Daisy(II)) was used to simplify the 3-step, in vitro procedure (TSP) to reduce the cost and labor involved in the determination of intestinal digestion of proteins. Four tests were conducted to study the effects of the type of pepsin (P-7012 and P-7000; Sigma, St. Louis, MO), the type of bags used for the incubation of samples (R510 and F57; Ankom Technology, Fairport, NY), the amount of sample per bag (0.5, 1, 2, or 5 g), and the number of bags per incubation bottle (5, 15, 20, or 30 bags) on the estimated intestinal digestion of proteins. A soybean meal sample heated at 170 degrees C for 0, 0.5, 1, 2, 4, 6, or 8 h was used in all preliminary tests to determine the optimum conditions of the technique. The intestinal digestion of 12 protein supplements was determined using the Daisy(II) as well as the proposed TSP techniques. Results using the 2 types of pepsin were highly correlated: P-7012 = (0.99 +/- 0.04 x P-7000) -0.29 +/- 2.33 (r2 = 0.99, P < 0.001, n = 14). Intestinal digestion of soybean meal samples obtained from the TSP assay were highly correlated with those obtained using the Daisy(II) incubator with Ankom R510 bags: Daisy(R510) = (1.37 +/- 0.06 x TSP) -15.45 +/- 3.85 (r2 = 0.98, P < 0.001, n = 14); and Ankom F57 bags: Daisy(F57) = (1.33 +/- 0.06 x TSP) -15.76 +/- 3.87 (r2 = 0.98, P < 0.001, n = 14). Although there was a bias in these equations, when the whole protocol was applied to the determination of intestinal digestion of the 12 protein supplements using the TSP or the Daisy(II) technique with the Ankom R510 bags, the data were highly correlated: (0.93 +/- 0.12 x TSP) + 6.78 +/- 9.09 (r2 = 0.84, P < 0.001, n = 12). The amount of sample per bag and the number of bags per incubation bottle did not affect the estimates of intestinal digestion of proteins. These results indicate that the use of up to 30 nylon bags (Ankom R510) with 5 g of sample in each Daisy(II) incubation bottle could be used to estimate intestinal digestion of proteins in ruminants.

Animal Feed↗

PubMed2006

Effects of alfalfa extract, anise, capsicum, and a mixture of cinnamaldehyde and eugenol on ruminal fermentation and protein degradation in beef heifers fed a high-concentrate diet.

Four Holstein heifers (360 +/- 22 and 450 +/- 28 kg of BW in Exp. 1 and 2, respectively) fitted with ruminal trocars were used in 4 x 4 Latin square designs to evaluate the effects on ruminal microbial fermentation of the following: Exp. 1, no additive, alfalfa extract (30 g/d, AEX), a mixture of cinnamaldehyde (0.18 g/d) and eugenol (0.09 g/d; CIE1), and AEX and CIE1 in combination; and Exp. 2, no additive, anise oil (2 g/d), capsicum oil (1 g/d), and a mixture of cinnamaldehyde (0.6 g/d) and eugenol (0.3 g/d). Heifers were fed a 90:10 concentrate:barley straw diet (16% CP; 25% NDF) for ad libitum intake. Each period consisted of 15 d for adaptation and 6 d for sampling. On d 16 to 18, DM and water intakes were measured. On d 19 to 21 ruminal contents were sampled at 0, 3, 6, 9, and 12 h after feeding to determine ruminal pH and the concentrations of VFA, L-lactate, large peptides, small peptides plus AA (SPep+AA), and ammonia N. On d 20 and 21, samples of ruminal fluid were collected at 0 and 3 h after feeding to determine protozoal counts. In Exp. 1, CIE1 and AEX decreased (P < 0.05) total DMI, concentrate DMI, and water intake. The increase (P < 0.05) in SPep+AA and the decrease (P < 0.05) in ammonia N when supplementing CIE1 suggest that deamination was inhibited. Treatment AEX increased (P < 0.05) the acetate to propionate ratio, which is less efficient for beef production. Treatment CIE1 increased (P < 0.05) counts of holotrichs. Effects of AEX and CIE1 were not additive for many of the measured metabolites. In Exp. 2, treatments had no effect on ruminal pH, total VFA concentration, and butyrate proportion. The capsicum oil treatment increased (P < 0.05) DMI, water intake, and SPep+AA N concentration and decreased (P < 0.05) acetate proportion, branched-chain VFA concentration, and large peptide N concentration. The cinnamaldehyde (0.6 g/d) and eugenol (0.3 g/d) treatment decreased (P < 0.05) water intake, acetate proportion, branched-chain VFA, L-lactate, and ammonia N concentrations and increased (P < 0.05) propionate proportion and SPep+AA N concentration. The anise oil treatment decreased (P < 0.05) acetate to propionate ratio, branched-chain VFA and ammonia N concentrations, and protozoal counts. The results indicate that at the doses used a mixture of cinnamaldehyde and eugenol, anise oil, and capsicum oil may be useful as modifiers of rumen fermentation in beef production systems.

Acrolein↗

PubMed2006

Plant extracts affect in vitro rumen microbial fermentation.

Different doses of 12 plant extracts and 6 secondary plant metabolites were incubated for 24 h in diluted ruminal fluid with a 50:50 forage:concentrate diet. Treatments were: control (no additive), plant extracts (anise oil, cade oil, capsicum oil, cinnamon oil, clove bud oil, dill oil, fenugreek, garlic oil, ginger oil, oregano oil, tea tree oil, and yucca), and secondary plant metabolites (anethol, benzyl salicylate, carvacrol, carvone, cinnamaldehyde, and eugenol). Each treatment was supplied at 3, 30, 300, and 3,000 mg/L of culture fluid. At 3,000 mg/L, most treatments decreased total volatile fatty acid concentration, but cade oil, capsicum oil, dill oil, fenugreek, ginger oil, and yucca had no effect. Different doses of anethol, anise oil, carvone, and tea tree oil decreased the proportion of acetate and propionate, which suggests that these compounds may not be nutritionally beneficial to dairy cattle. Garlic oil (300 and 3,000 mg/L) and benzyl salicylate (300 and 3,000 mg/L) reduced acetate and increased propionate and butyrate proportions, suggesting that methane production was inhibited. At 3,000 mg/L, capsicum oil, carvacrol, carvone, cinnamaldehyde, cinnamon oil, clove bud oil, eugenol, fenugreek, and oregano oil resulted in a 30 to 50% reduction in ammonia N concentration. Careful selection and combination of these extracts may allow the manipulation of rumen microbial fermentation.

Ammonia↗

PubMed2006

Effect of essential oil active compounds on rumen microbial fermentation and nutrient flow in in vitro systems.

Two experiments were conducted to determine the effects of several essential oil active compounds on rumen microbial fermentation. In the first experiment, 4 doses (5, 50, 500, and 5,000 mg/L) of 5 essential oil compounds were evaluated using in vitro 24-h batch culture of rumen fluid with a 60:40 forage:concentrate diet (18% crude protein; 30% neutral detergent fiber). Treatments were control (CON), eugenol (EUG), guaiacol, limonene, thymol (THY), and vanillin. After 24 h, the pH was determined, and samples were collected to analyze ammonia N and volatile fatty acids (VFA). The highest dose of all compounds decreased total VFA concentration and increased the final pH. Eugenol at 5 mg/L tended to reduce the proportion of acetate and the acetate to propionate ratio, at 50 and 500 mg/L tended to reduce ammonia N concentration, and at 500 mg/L reduced the proportion of propionate and branched-chain VFA concentration, without affecting total VFA concentration. All other treatments had minor effects or changes occurred only after total VFA concentration decreased. In the second experiment, 8 dual-flow continuous culture fermenters (1,320 mL) were used in 3 replicated periods (6 d of adaptation and 3 d of sampling) to study the effects of THY and EUG on rumen microbial fermentation. Fermenters were fed 95 g/d of DM of a 60:40 forage:concentrate diet (18% crude protein; 30% neutral detergent fiber). Treatments were CON, 10 mg/L of monensin (positive control), and 5, 50, or 500 mg/L of THY and EUG, and were randomly assigned to fermenters within periods. During the last 3 d of each period, samples were taken at 0, 2, 4, and 6 h after the morning feeding and analyzed for peptides, amino acids, and ammonia N concentrations, and total and individual VFA concentrations. Monensin changed the VFA profile as expected, but inhibited nutrient digestion. Eugenol and THY decreased total VFA concentration and changed the VFA profile, and only 5 mg/L of THY tended to reduce the proportion of acetate, increased the proportion of butyrate, and increased the large peptides N concentration without decreasing total VFA concentration. Most of these essential oil compounds demonstrated their antimicrobial activity by decreasing total VFA concentration at high doses. However, EUG in batch fermentation and 5 mg/L of THY in continuous culture modified the VFA profile without decreasing total VFA concentration, and EUG in batch fermentation decreased ammonia N concentration.

Acetates↗

PubMed2005

Screening for the effects of natural plant extracts at different pH on in vitro rumen microbial fermentation of a high-concentrate diet for beef cattle.

Six natural plant extracts and three secondary plant metabolites were tested at five doses (0, 0.3, 3, 30, and 300 mg/L) and two different pH (7.0 and 5.5) in a duplicate 9 x 5 x 2 factorial arrangement of treatments to determine their effects on in vitro microbial fermentation using ruminal fluid from heifers fed a high-concentrate finishing diet. Treatments were extracts of garlic (GAR), cinnamon (CIN), yucca (YUC), anise (ANI), oregano (ORE), and capsicum (CAP) and pure cinnamaldehyde (CDH), anethole (ATL), and eugenol (EUG). Each treatment was tested in triplicate and in two periods. Fifty milliliters of a 1:1 ruminal fluid-to-buffer solution were introduced into polypropylene tubes supplied with 0.5 g of DM of a 10:90 forage:concentrate diet (15.4% CP, 16.0% NDF; DM basis) and incubated for 24 h at 39 degrees C. Samples were collected for ammonia N and VFA concentrations. The decrease in pH from 7.0 to 5.5 resulted in lower (P < 0.05) total VFA, ammonia N, branched-chain VFA concentration, acetate proportion, and acetate:propionate, and in a higher (P < 0.05) propionate proportion. The interaction between pH and doses was significant for all measurements, except for ATL and CDH for butyrate, ATL and EUG for acetate:propionate ratio, and ORE for ammonia N concentration. The high dose of all plant extracts decreased (P < 0.05) total VFA concentrations. When pH was 7.0, ATL, GAR, CAP, and CDH decreased (P < 0.05) total VFA concentration, and ANI, ORE, CIN, CAP, and CDH increased (P < 0.05) the acetate:propionate. The CIN, GAR, CAP, CDH, ORE, and YUC decreased (P < 0.05), and EUG, ANI, and ATL increased (P < 0.05) ammonia N concentration. The effects of plant extracts on the fermentation profile when pH was 7.0 were not favorable for beef production. In contrast, when pH was 5.5, total VFA concentration did not change (ATL, ANI, ORE, and CIN) or increased (P < 0.05) (EUG, GAR, CAP, CDH, and YUC), and the acetate:propionate (ORE, GAR, CAP, CDH, and YUC) decreased (P < 0.05), which would be favorable for beef production. Ammonia N (ATL, ANI, CIN, GAR, CAP, and CDH) and branched-chain VFA (ATL, EUG, ANI, ORE, CAP, and CDH) concentrations also were decreased (P < 0.05), suggesting that deamination was inhibited. Results indicate that the effects of plant extracts on ruminal fermentation in beef cattle diets may differ depending on ruminal pH. When pH was 5.5, GAR, CAP, YUC, and CDH altered ruminal microbial fermentation in favor of propionate, which is more energetically efficient.

Ammonia↗

PubMed2005

Changes in ruminal fermentation and protein degradation in growing Holstein heifers from 80 to 250 kg fed high-concentrate diets with different forage-to-concentrate ratios.

Six Holstein heifers (initial BW = 65.2 +/- 1.8 kg) fitted with ruminal cannulas were used in a repeated measures trial to assess the effect of age and forage-to-concentrate ratio on ruminal fermentation end products and in situ degradation kinetics of four plant protein supplements (soybean meal, sunflower meal, peas, and lupin seeds). Alfalfa hay also was incubated in situ to estimate NDF degradation. Three experimental periods were conducted at 13, 27, and 41 wk of age. Heifers were fed one of two diets, 12:88 vs. 30:70 forage-to-concentrate ratio (DM basis), offered as total mixed ration on an ad libitum basis. Intakes of DM, OM, CP, NDF, and ADG were not affected (P > or = 0.105) by diet. The 30:70 diet resulted in faster (P = 0.045) fluid passage rate and decreased (P = 0.015) ammonia N concentration compared with the 12:88 diet, but no differences (P > or = 0.244) were detected in ruminal pH and total VFA concentration between diets. The rate of degradation and the effective degradability of N in protein supplements was greater with the 30:70 diet for peas (P < or = 0.008) and lupin seeds (P < or = 0.02), and in the 12:88 diet for sunflower meal (P < or = 0.06). Degradation of NDF of alfalfa hay was low with both diets (18.5 and 23.7 % for 12:88 and 30:70, respectively); however, the rate and extent of DM and NDF degradation were greater (P < or = 0.016) with the 30:70 diet, suggesting a higher cellulolytic activity. Total VFA concentration and the proportion of propionate increased (P < or = 0.035), and the acetate proportion decreased (P = 0.021) with age. Average pH, ammonia N concentration, and passage rates were not affected (P > or = 0.168) by age. Degradation rate and effective degradability of N of sunflower meal, peas, lupin seeds, and of DM of alfalfa hay increased (P < or = 0.08) with age, but degradation kinetics of NDF of alfalfa hay was not affected (P > or = 0.249). The increase in the rate and extent of N degradation with age would suggest an increase in proteolytic activity, and the changes in the fermentation pattern may reflect an increase in amylolytic activity caused mainly by an increase in the gross intake of nonstructural carbohydrates and by adaptation of ruminal microflora after long exposure to these nutrients.

Acetates↗

PubMed2005

Effects of cinnamaldehyde and garlic oil on rumen microbial fermentation in a dual flow continuous culture.

Eight continuous culture fermentors inoculated with ruminal liquor from heifers fed a 50:50 alfalfa hay:concentrate diet (17.6% crude protein, 28.0% neutral detergent fiber) were used in 3 replicated periods to study the effects of cinnamaldehyde (CIN) and garlic oil (GAR) on rumen microbial fermentation. Treatments were no additive (negative control); 1.25 mg/L (MON) and 12.5 mg/L (MON10) of the ionophore antibiotic monensin (positive control); 31.2 mg/L CIN (CIN) and 312 mg/L (CIN10) of CIN; and 31.2 mg/L GAR (GAR) and 312 mg/L (GAR10) of GAR (Allium sativa). The MON10 caused expected changes in microbial fermentation patterns (a decrease in fiber digestion, ammonia N concentration, and proportions of acetate and butyrate; an increase in the proportion of propionate; and a trend to increase small peptide plus AA N concentration). The CIN decreased the proportion of acetate and branch-chained volatile fatty acids (VFA) and increased the proportion of propionate; CIN10 decreased the proportion of acetate and increased the proportion of butyrate compared with the control. The GAR10 increased the proportion of propionate and butyrate and decreased the proportion of acetate and branch-chained VFA compared with the control. The GAR10 also increased the small peptide plus amino acid N concentration, although no effects were observed on large peptides or ammonia N concentrations. The CIN and GAR10 resulted in similar effects as monensin, with the exception of the effects on the molar proportion of butyrate, which suggests that they might have a different mode of action in affecting in vitro microbial fermentation.

Acetates↗

PubMed2005

Effect of garlic oil and four of its compounds on rumen microbial fermentation.

Different concentrations (3, 30, 300, and 3000 mg/L of culture fluid) of garlic oil (GAR), diallyl sulfide (DAS), diallyl disulfide (DAD), allicin (ALL), and allyl mercaptan (ALM) were incubated for 24 h in diluted ruminal fluid with a 50:50 forage:concentrate diet (17.7% crude protein; 30.7% neutral detergent fiber) to evaluate their effects on rumen microbial fermentation. Garlic oil (30 and 300 mg/L), DAD (30 and 300 mg/L), and ALM (300 mg/L) resulted in lower molar proportion of acetate and higher proportions of propionate and butyrate. In contrast, at 300 mg/L, DAS only increased the proportion of butyrate, and ALL had no effects on volatile fatty acid proportions. In a dual-flow continuous culture of rumen fluid fed the same 50:50 forage:concentrate diet, addition of GAR (312 mg/L), DAD (31.2 and 312 mg/L), and ALM (31.2 and 312 mg/L) resulted in similar changes to those observed in batch culture, with the exception of the lack of effect of DAD on the proportion of propionate. In a third in vitro study, the potential of GAR (300 mg/L), DAD (300 mg/L), and ALM (300 mg/L) to decrease methane production was evaluated. Treatments GAR, DAD, and ALM resulted in a decrease in methane production of 73.6, 68.5, and 19.5%, respectively, compared with the control. These results confirm the ability of GAR, DAD, and ALM to decrease methane production, which may help to improve the efficiency of energy use in the rumen.

Allyl Compounds↗

PubMed2004

Effects of natural plant extracts on ruminal protein degradation and fermentation profiles in continuous culture.

Eight dual-flow continuous culture fermenters were used in four consecutive periods of 10 d to study the effects of six natural plant extracts on ruminal protein degradation and fermentation profiles. Fermenters were fed a diet with a 52:48 forage:concentrate ratio (DM basis). Treatments were no extract (CTR), 15 mg/kg DM of a mixture of equal proportions of all extracts (MIX), and 7.5 mg/kg DM of extracts of garlic (GAR), cinnamon (CIN), yucca (YUC), anise (ANI), oregano (ORE), or pepper (PEP). During the adaptation period (d 1 through 8), samples for ammonia N and VFA concentrations were taken 2 h after feeding. On d 9 and 10, samples for VFA (2 h after feeding), and peptide, AA, and ammonia N concentrations (0, 2, 4, 6, and 8 h after feeding) were also taken. Differences were declared at P < 0.05. During the adaptation period, total VFA and ammonia N concentrations were not affected by treatments. The acetate proportion was higher from d 2 to 6 in CIN, GAR, ANI, and ORE, and the propionate proportion was lower from d 2 to 4 in CIN and GAR, and from d 2 to 5 in ANI and ORE, compared with CTR. However, the proportion of individual VFA (mol/100 mol) was similar in all treatments after d 6, except for valerate in d 9 and 10, which was lower in PEP (2.8 +/- 0.27) compared with CTR (3.5 +/- 0.27). The average peptide N concentration was 31% higher in MIX, and 26% higher in CIN and YUC compared with CTR (6.5 +/- 1.07 mg/100 mL). The average AA N concentration was 17 and 15% higher in GAR and ANI, respectively, compared with CTR (7.2 +/- 0.77 mg/100 mL). The average ammonia N concentration was 31% higher in ANI and 25.5% lower in GAR compared with CTR (5.5 +/- 0.51 mg/100 mL). The accumulation of AA and ammonia N in ANI suggested that peptidolysis and deamination were stimulated. The accumulation of AA N and the decrease in ammonia N in GAR suggests that deamination was inhibited. The accumulation of peptide N and the numerical decrease in AA N in CIN suggest that peptidolysis was inhibited. Results indicate that plant extracts modified ruminal fermentation, but microbes were adapted to some extracts after 6 d of fermentation. Therefore, data from short-term in vitro fermentation studies may lead to erroneous conclusions, and should be interpreted with caution. Careful selection of these additives may allow the manipulation of protein degradation in the rumen.

Acetates↗

PubMed2004

Effects of fiber content and particle size of forage on the flow of microbial amino acids from continuous culture fermenters.

Eight dual-flow continuous culture fermenters (1320 mL) were used in two 10-d consecutive periods to study the effects of fiber content and particle size on rumen fermentation, nutrient flow, and the profile and flow of amino acids (AA) from microbial origin. Treatments were arranged in a 2 x 2 factorial; the main factors were fiber content (high fiber [HF] = 67% alfalfa hay, 33% concentrate; low fiber [LF] = 39% alfalfa hay, 61% concentrate) and forage stem particle size (ground not to pass a 3-mm sieve = large size [LS]; ground to pass a 1-mm sieve = small size [SS]). On the last day of the experiment, liquid- (LAB) and solid- (SAB) associated bacteria were isolated from each fermenter for chemical analysis. Microbial N and AA flows were estimated using LAB or SAB composition data. Total volatile fatty acid concentration was higher for LF (122 mM) than for HF (102 mM). The proportion of acetate was higher for HF (63.5%) than for LF (58.2%). When SS was fed instead of LS, there was a reduction in the acetate proportion (63.4% vs 58.3%, respectively) and in the acetate to propionate ratio (3.13 vs. 2.41, respectively). Bacterial N flow was higher, and dietary N flow was lower, in SS compared with LS when LAB were used for calculations. Efficiency of microbial protein synthesis (EMPS) was affected by particle size, when LAB were used for calculations, and by fiber content, when SAB were used for calculations. The AA profile of LAB differed from SAB in 4 of 16 AA. The fiber content and particle size had small effects on microbial AA profile. However, the bacterial AA flow was higher in 13 of 16 AA, when SAB instead of LAB were used for calculations. Estimates of bacterial N flow, EMPS, AA profile, and flows of microbial origin were dependent on the type of microbial population used for calculations. The representativeness of the microbial samples is essential for the accurate prediction of the AA flow from microbial origin.

Amino Acids↗

PubMed2002

Effects of pH and pH fluctuations on microbial fermentation and nutrient flow from a dual-flow continuous culture system.

Eight dual-flow continuous culture fermenters (1400 ml) were used in two consecutive periods to study the effects of pH and pH fluctuations on microbial fermentation and nutrient flow. Fermenters were maintained at 39 degrees C, with solid and liquid dilution rates of 5 and 10%/h, respectively, and fed continuously a 60% alfalfa hay and 40% concentrate diet (18.9% crude protein, 36.6% neutral detergent fiber, 17.6% acid detergent fiber). Treatments were high pH (constant at 6.4); low pH (constant at 5.7); cycles of 4 h at pH 6.4 and 4 h at pH 5.7; and pH constant at 6.4, except for two 30-min drops per day to pH 5.7, followed by a 3-h slow recovery to pH 6.4. The low pH (constant at 5.7) produced lower apparent dry matter, neutral detergent fiber and acid detergent fiber digestion, lower total and branch-chained volatile fatty acid concentrations, and lower acetate and higher propionate proportions than high pH (constant at 6.4). There were no differences in these estimates between constant high pH and the two treatments that alternated high pH and low pH. The constant low pH reduced protein degradation and increased nonammonia N and dietary N flow compared with constant high pH. The pH treatments had no effect on bacterial N flow or efficiency of microbial protein synthesis. Flow of essential amino acids was highest for constant low pH and lowest for constant high pH. Results indicate that constant low pH reduced fiber and protein digestion and increased the flow of total and some individual amino acids. However, the effects of transitory decreases of pH were either small or insignificant with the conditions tested in this study.

Amino Acids↗

PubMed2001

Effect of nitrogen source in high-concentrate, low-protein beef cattle diets on microbial fermentation studied in vivo and in vitro.

In Exp. 1, four Holstein heifers (112+/-5.5 kg BW) fitted with ruminal cannulas were used in a 4 x 4 Latin square to evaluate the effects of N source on ruminal fermentation and urinary excretion of purine derivatives. A 2 x 2 factorial arrangement of treatments was used; the factors were the type of protein source (soybean meal, SBM, vs a 50:50 mixture of fish meal and corn gluten meal, FMCGM) and the partial substitution of protein source by urea (with vs without). Heifers were allowed to consume concentrate and barley straw on an ad libitum basis. Barley straw:concentrate ratio (12:88) and average ruminal pH (6.25) were not affected (P > 0.05) by treatment. Ruminal NH3 N concentration and urinary excretion of purine derivatives were not affected (P > 0.05) by supplemental N source. In situ CP degradability of supplemented SBM was very low (50%). In Exp. 2, eight dual-flow continuous-culture fermenters were used to study diet effects on microbial fermentation and nutrient flow, using forage:concentrate ratio, solid and liquid passage rates, and pH fluctuation to simulate in vivo conditions. The treatment containing SBM without urea reached the greatest total VFA concentration (P < 0.01), molar percentage of acetate (P < 0.05), and NH3 N concentration (P < 0.05), followed by treatments with partial substitution of protein source by urea, and finally by the treatment containing FMCGM. True OM digestion tended to increase (P = 0.13) in treatments containing SBM. These results suggest that amino N from SBM and NH3 N concentration stimulated nutrient digestion. Microbial protein synthesis was lowest in treatments with FMCGM and without urea, indicating that rapidly available N limited microbial growth. The low CP degradability of SBM observed may have contributed to the limitation in N supply for microbial growth. Efficiency of microbial protein synthesis increased in treatments containing urea (P < 0.05). Protein source affected total (P < 0.05) and essential AA (P < 0.10) flows, which were greater in treatments containing FMCGM. Partial replacement of protein supplements by urea did not affect total and essential AA flows. Because mean dietary protein contribution to total N effluent was 46%, the AA profile of supplemental protein sources had a great impact on total AA flow and its profile.

Amino Acids↗

PubMed2000

Effects of protein concentration and degradability on performance, ruminal fermentation, and nitrogen metabolism in rapidly growing heifers fed high-concentrate diets from 100 to 230 kg body weight.

Twenty crossbred heifers (101 +/- 4.5 kg BW) were used to examine the effects of protein concentration and degradability on performance, ruminal fermentation, nutrient digestion, N balance, and urinary excretion of purine derivatives. Heifers were offered concentrate and barley straw for ad libitum consumption. Two protein concentrations (17 vs 14%, DM basis) and two protein sources differing in ruminal degradability (58 vs 42% of CP for soybean meal and treated soybean meal, respectively) were tested. The experiment was divided into four consecutive 28-d periods to evaluate the age (period) effect. Increasing protein concentration and degradability did not improve ADG or intake (P > .05). The increase in urinary N excretion (P < .001) in heifers fed 17% CP suggests that N was in excess of requirements. When the low-degradable protein source was supplemented and(or) CP concentration was low, ruminal NH3 N concentrations fell below 5 mg/100 mL. Urinary excretion of purine derivatives was not affected (P > .05) by protein concentration and degradability, suggesting that in high-concentrate diets NH3 N concentration was not limiting microbial growth. Total VFA concentration decreased (P < .001) and the acetate:propionate ratio increased (P < .01) with advancing period, suggesting an increase in ruminal absorption capacity and an increase in fiber fermentation. The decrease in ruminal NH3 N concentration in the last period suggests a greater use of NH3 N by microorganisms. This hypothesis is supported by the increase (P < .001) in urinary excretion of allantoin and estimated duodenal flows of purine bases and microbial protein with advancing period. Reducing CP concentration and increasing ruminal undegradable protein supply did not affect animal performance or estimated duodenal flow of microbial protein in rapidly growing heifers fed high-concentrate diets.

Animal Feed↗

PubMed1997

Influence of kid rearing systems on milk composition and yield of Murciano-Granadina dairy goats.

One-hundred eight lactations of Murciano-Granadina goats from different years were used to compare two kid rearing systems. Goats were separated into two groups: suckling and milking. Dams in the suckling group were milked once daily until kids were weaned (wk 0 to 7) and then were milked twice daily. Dams in the milking group were separated from their kids at 48 h after birth; then, kids were raised artificially, and goats were milked twice daily. Total milk yield was estimated according to the oxytocin method during suckling. Stage of lactation, parity, prolificacy, and year effects on milk yield and composition were also studied. As expected, during the first 7 wk of lactation, marketable milk was higher for dams that were milked than for dams that were suckled. Neither milk yield nor milk composition throughout the entire lactation was affected by group or prolificacy with the exception of the percentage of milk CP. The lactation curve peaked at wk 4 or 5 and declined slowly afterward. First parity goats had the lowest milk yield but the highest fat and protein percentages. Third parity goats had the highest milk yield. The separation of kids from their dams after birth did not affect total lactation performance because of the minimal importance of the neuroendocrine milk ejection reflex in goats compared with that of other ruminants.

Animals↗