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PubMed1979

Ovine coccidiosis: comparison of the effects of monensin and aureomycin on lambs infected with coccidia.

Lambs naturally infected with mixed species of Eimeria were fed monensin (30 mg/kg of feed) and aureomycin (10 mg/kg of feed) separately and in combination. An evaluation was made of the efficacy of the treatments in the suppression of oocyst production. Comparisons were made of the parasitic damage to the intestinal surface. Performance of the lambs was measured by weight gains and feed efficiency. Monensin given separately or in combination with aureomycin produced decreases in oocyst counts that were not significantly different from those in the lambs given only aureomycin. Body weight gains and feed efficiency were best in the aureomycin-treated group, and less so in the monensin-treated and the control groups. Animals fed the monensin-aureomycin combination had the poorest weight gains and feed efficiency. Scanning electron microscopy indicated that the groups fed monensin or aureomycin separately had morphologically normal intestinal surfaces. This was in contrast to the control group and the group fed the monensin-aureomycin combination, wherein there was disrupted intestinal surface morphology.

Animals↗

PubMed2000

Choline is required by tilapia when methionine is not in excess.

Choline is essential in diets fed to most young vertebrates, but previous studies did not confirm the essentiality of choline in diets fed to tilapia. Two experiments were conducted to evaluate the essentiality of dietary choline in such diets. The basal diet used in both experiments contained 32 g crude protein/100 g diet (10.1 g crude protein from casein and gelatin, and 21.9 g from a crystalline L-amino acid mixture). The total sulfur amino acid (TSAA) concentration of the basal diet was 0.28 g/100 g diet, Met:Cys 89:11. In Experiment 1, a 4x2 design was used in which crystalline L-methionine was added to the basal diet resulting in four levels of TSAA (0.28, 0.50, 0.75 or 1.0 g/100 g diet, Met:Cys 89:11, 94:6, 96:4, or 97:3, respectively). At each level of TSAA, diets also contained either 0 or 1 g choline/kg diet supplied as choline chloride. Weight gain, feed efficiency (FE) and serum methionine concentrations were significantly affected by dietary TSAA concentration, but not by dietary choline concentration or the interaction between TSAA and choline. Weight gain, feed efficiency and serum methionine concentrations indicated that the TSAA requirement was 0.5 g/100 g diet. In the second experiment, diets were formulated to contain either 0.28 or 0.5 g TSAA/100 g diet, Met:Cys 89:11 or 94:6, respectively, and graded levels of choline ranging from 1 to 4 g/kg diet in gradations of 1 g/kg. Dietary methionine significantly affected weight gain and FE, whereas dietary choline significantly affected weight gain, FE and survival, and the interaction of methionine and choline significantly affected weight gain. Fish fed diets containing 0.5 g TSAA/100 g diet and 3 g choline chloride/kg diet exhibited the highest weight gain, feed efficiency and survival. On the basis of these data, it seems clear that juvenile tilapia require choline in certain dietary formulations.

Analysis of Variance↗

PubMed1976

Feeding behavior in monkeys with and without lesions of the hypothalamus.

In monkeys (Macaca mulatta) without hypothalamic lesions, food intake was found to increase with increasing age and body weight; however, food intake per kilogram body weight showed a decline over the same period of time. As the animals became older, the amount of food intake converted to body weight decreased dramatically (feeding efficiency). Water intake was shown to be closely coupled to food intake. Both daily food and water-intake data were highly reliable over a period of years. Monkeys with ventromedial hypothalamic lesions exhibited hyperphagia and increased feeding-efficiency ratios and eventual obesity. The obese animals developed symptoms of diabetes mellitus. Animals with lesions restricted primarily to the arcuate nucleus showed no hyperphagia but increased feeding efficiency. These animals exhibited decreased growth hormone release and a transitory elevation of serum insulin.

Age Factors↗

PubMed2002

Utilization of Bt corn residues by grazing beef steers and Bt corn silage and grain by growing beef cattle and lactating dairy cows.

Three experiments were conducted to evaluate the impact of the Bacillus thuringiensis (Bt)-11 transformation event in two parental corn hybrids differing in date of maturity on beef and dairy cattle performance. Sixteen lactating Holstein dairy cows in replicated 4 x 4 Latin squares were assigned to four diets in a 2 x 2 factorial arrangement: Bt vs non-Bt trait and early- vs late-maturing corn hybrids. The diets contained 40% of the test corn silage plus 28% corn grain from the same corn hybrid (DM basis). There was no effect of the Bt trait on efficiency of milk production, ruminal pH, acetate:propionate ratio, or in situ digestion kinetics of NDF. The early-maturing corn hybrids resulted in greater total VFA concentrations in the rumen and efficiency of 4% fat-corrected milk production than the later-maturing hybrids (P < 0.05). Sixty-seven steer calves were used in a 70-d corn residue grazing trial for the late-maturing corn hybrids only. Daily BW gain of steers was similar for those grazing Bt and non-Bt corn residues, and the steers exhibited no grazing preference between Bt and non-Bt corn residue. One hundred twenty-eight steer calves were assigned to four silage-based growing diets in a 2 x 2 factorial arrangement: Bt vs non-Bt trait and early- vs late-maturing corn hybrids. The diets contained 90% corn silage and 10% supplement (DM basis). The DMI was higher for steers fed Bt compared with non-Bt hybrids (P < 0.02). An interaction (P < 0.03) was observed for feed efficiency between hybrid genotype and incorporation of the Bt trait. Feed efficiency was greater (P < 0.05) for steers fed the later-maturing non-Bt hybrid compared with the later-maturing Bt hybrid; however, feed efficiency was similar between steers fed early-maturing Bt and non-Bt corn silages. Steers fed the early-maturing hybrid gained 11% faster and were 7% more efficient compared with those fed the late-maturing hybrid. These latter results agree with the dairy experiment in which the early-maturing hybrid resulted in 5% greater efficiency of milk production than the later-maturing corn hybrid. In all experiments, incorporation of the Bt trait into corn had no consistent effect on cattle performance. In addition, background genetics of the corn hybrids appeared to have a more consistent impact on performance than did presence of the Bt trait.

Animal Feed↗

PubMed1995

Comparison of dietary 25-hydroxycholecalciferol and cholecalciferol in broiler chickens.

We conducted a series of 10 feeding trials involving over 36,000 broilers. The effects of various dietary levels of cholecalciferol (vitamin D3) or 25-hydroxycholecalciferol (25-OH-D3) were compared using a "basal" dosage level of 69 micrograms/kg feed, as well as levels ranging from .5 to 1.5 times the basal level. For all 10 studies, average body weight increased by an average of .042 +/- .03 kg (P < .001) and adjusted feed efficiency decreased (improved) by an average of .026 +/- .0046 kg/kg (P < .001) in birds fed 25-OH-D3 in comparison to those fed vitamin D3 at the basal level. Changes in mortality were not detected. Evaluation of different dietary levels of 25-OH-D3 revealed a significant dose-response relationship, with maximal effects on weight gain, feed efficiency, and breast meat yield being observed in the range of 50 to 70 micrograms/kg feed. Preliminary studies with different levels of vitamin D3 suggested no additional benefits on weight gain or feed efficiency with higher dietary levels of vitamin D3. Serum 25-OH-D3 concentrations increased more rapidly in birds fed 25-OH-D3 than in birds fed vitamin D3. There were significant correlations with body weight, feed conversion, and serum 25-OH-D3 concentrations, with no correlations observed between serum 1,25-(OH)2D3 concentrations and these variables.

Analysis of Variance↗

PubMed1990

Performance and plasma amino acids of growing calves fed corn silage supplemented with ground soybeans, fishmeal and rumen-protected lysine.

A 100-d growth study was conducted to evaluate performance and plasma amino acid (AA) responses of 96 crossbred beef calves (220 kg) with ad libitum access to corn silage and supplemented with ground soybeans (GSB) with or without added fishmeal (FM) and (or) rumen-protected lysine (Lys). Calves were allotted by breed, sex and weight to four treatments with three replicate pens of eight calves per pen. The treatments were: GSB, GSB + Lys, GSB + FM and GSB + FM + Lys. The isonitrogenous supplements were top-dressed on corn silage once daily at a level of 2.27 kg/hd, with FM providing one-half of the supplemental N in FM-containing supplements. The Lys-containing supplements provided a daily intake of 6.0 g/hd of rumen-protected Lys. Dry matter intake was similar (P less than .10) for all treatments. Overall ADG and feed efficiency of GSB calves averaged .83 kg/d and 7.39 kg feed/kg gain, respectively, and were 14% lower than the mean of calves fed supplements containing FM and(or) Lys. Lysine was not the principal factor limiting growth because the inclusion of Lys alone in the GSB-containing supplements did not improve (P greater than .10) ADG, feed efficiency or plasma AA concentrations. In contrast, FM supplementation increased (P less than .05) ADG, feed efficiency and plasma concentrations of total AA, total essential AA and total nonessential AA. The inclusion of Lys in the GSB + FM-containing supplement resulted in no further improvement (P greater than .10) in performance.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗

PubMed1980

Blood constituents of yeast fed chicks.

Two experiments on broiler chicks raised to 4 weeks of age were carried out to study the effects of replacing soybean protein in a semisynthetic diet with yeast protein from molasses (CEPAH). Criteria measured were body weight, feed efficiency, plasma urea nitrogen, serum uric acid, serum total protein, albumin, globulin and albumin-globulin ratios. Analysis of the data showed that yeast protein produced from molasses depressed growth and feed efficiency at levels 10, 15, and 20% of the diet. The effects of yeast protein on blood nitrogenous constituents were variable and not significant, but in general, the inclusion of yeast protein caused an increase in serum albumin and a decrease in serum globulin resulting in a higher albumin-globulin ratio. The changes observed in blood nitrogenous constituents in this study do not explain all the detrimental effects of yeast protein on growth and feed efficiency of chicks receiving high levels of such protein.

Animals↗

PubMed1976

Generation and compensation of the cancer cachectic process by spontaneous modification of feeding behavior.

Daily food intake and corresponding feeding activity (measured as duration) and feeding efficiency (amount of food ingested per unit of feeding activity) were measured both in normal Sprague-Dawley and Buffalo rats and during growth of Walker 256 and 4M mammary carcinomas in Sprague-Dawley rats and of Morris 5123 hepatoma in Buffalo rats. Estimates of meal size and frequency were also obtained. Growth of the carcinomas produced a decline in feeding activity accompanied, early in tumor growth, by a compensatory increase in feeding efficiency with no resultant effect on food intake. This compensated decline in feeding activity was due to reduction in average meal duration. Later, meal frequency was also reduced, with further reduction in feeding activity and reduction in food intake. There was little change in average meal size. The hepatoma produced a different detailed pattern of effect on feeding behavior. These effects are not nonspecific reactions to foreign tissue. The effects imply behavioral compensation for the breakdown of a rapidly responding physiological control of food intake and can be interpreted in terms of successive impairment of feeding control mechanisms that have different response rates and different behavioral modes.

Animals↗

PubMed2004

Influence of method of whole wheat inclusion and xylanase supplementation on the performance, apparent metabolisable energy, digestive tract measurements and gut morphology of broilers.

1. The aim of the present study was to examine the influence of whole wheat inclusion and xylanase supplementation on the performance, apparent metabolisable energy (AME), digesta viscosity, and digestive tract measurements of broilers fed on wheat-based diets. The influence of the method of whole wheat inclusion (pre- or post-pelleting) was also compared. A 3 x 2 factorial arrangement of treatments was used with three diet forms (648 g/kg ground wheat [GW], GW replaced by 200 g/kg of whole wheat before [WW1] or after cold-pelleting [WW2]) and two xylanase levels (0 and 1000 XU/kg diet). 2. Birds given diets containing whole wheat had improved weight gains, feed efficiency and AME compared to those fed on diets containing ground wheat. The relative gizzard weight of birds fed WW2 diets was higher than in those fed GW and WW1 diets. Pre-pelleting inclusion of whole wheat had no effect on relative gizzard weight. Post-pelleting inclusion of whole wheat resulted in greater improvements in feed efficiency and AME than the pre-pelleting treatment. 3. Xylanase supplementation significantly improved weight gain, feed efficiency and AME, irrespective of the wheat form used. Viscosity of the digesta in the duodenum, jejunum and ileum were reduced by xylanase addition. Xylanase supplementation reduced the relative weight of the pancreas. 4. Neither xylanase supplementation nor whole wheat inclusion influenced the relative weight and length of the small intestine. 5. Xylanase supplementation increased ileal villus height. A significant interaction between diet form and xylanase was observed for ileal crypt depth. Xylanase supplementation had no effect on crypt depth in birds fed on diets containing GW, but increased the crypt depth in WW2 diets. No significant effects of diet form and xylanase supplementation were observed for the thickness of the tunica muscularis layer of gizzard or villus height, crypt depth, goblet cell numbers or epithelial thickness in the ileum. 6. Improved performance observed with post-pelleting inclusion of whole wheat was associated with increased size of the gizzard and improved AME. The gizzard development hypothesis, however, will not explain the improvements observed with pre-pelleting inclusion of whole wheat, suggesting the involvement of other factors.

Animal Nutritional Physiological Phenomena↗

PubMed1987

Alterations in performance and muscle composition of young turkeys in response to dietary amino acid balance.

Two experiments were performed to determine the effects of essential (EAA) and nonessential amino acid (NEAA) supplementation of a 22% protein corn-soybean meal diet on the performance of muscle composition of male Large White turkeys from 7 to 21 days of age. The 22% protein diet was supplemented with DL-methionine (MET) or a combination of MET and L-lysine (LYS) in Experiment 1. Additions in Experiment 2 included MET; and EAA mixture of MET, LYS, L-threonine, and L-valine; and a mixture of NEAA equal to 2% crude protein combined with either the MET or EAA supplement. Controls received a 30% protein diet. Each diet was fed ad libitum to five and four pens of eight poults in Experiment 1 and 2, respectively. Maximum performance was obtained with the 30% protein diet in both experiments. Methionine was confirmed as the first-limiting amino acid in the 22% protein diet. Lysine addition to the MET-supplemented low protein diet adversely affected performance in Experiment 1, suggesting that LYS was not the second most limiting amino acid. The EAA supplement elicited growth equal to the 30% protein diet although feed efficiency remained inferior. Increases in growth and feed efficiency were associated with NEAA addition. Changes in the weights of the pectoralis and gastrocnemius muscles due to diet, albeit directly related to body weight, were independent of muscle composition. The composition of gastrocnemius muscle was relatively insensitive to dietary manipulation. Pectoral ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) concentrations increased with a decrease in dietary protein. Amino acid supplementation reduced DNA concentration without altering muscle RNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗

PubMed1992

Effect of duration of fasting on postmolt laying hen performance.

Two experiments were conducted to examine the effects of varying length of feed withdrawal on postmolt laying hen performance. Commercial laying hens (65 wk of age) were fed continuously or fasted for 4 or 10 days in Experiment 1 and fed continuously or fasted for 4, 7, or 14 days in Experiment 2. Egg production performance was evaluated for 35 wk of production following initiation of fasting. Hen-day egg production (Weeks 1 to 35) and egg weight (Weeks 5 to 35) did not differ between treatments in Experiment 1; however, in Experiment 2, egg production was depressed for the 14-day fasted hens compared with the fed hens. Lower egg weight also occurred for the 14-day fasted hens compared with the fed, 4-, or 7-day fasted hens in Experiment 2. Egg yield (grams of egg per hen per day) for Weeks 5 to 35 was lower for fed hens versus the 4- or 10-day fasted groups in Experiment 1, but no treatment differences occurred in Experiment 2. Feed efficiency (grams of egg per gram of feed) for Weeks 5 to 13 was not affected by length of fasting in Experiment 1, but feed efficiency of hens fasted for 14 days was lower (P less than .05) than that of hens on other treatments in Experiment 2. Egg specific gravity was highest for hens fasted for 10 or 14 days and was lowest for fed hens, with egg specific gravity for hens fasted for 4 or 7 days being intermediate (P less than or equal to .05). The results indicated that fasting periods of less than 10 days may yield satisfactory egg production and egg weight but that eggshell quality may be enhanced by using fasting periods of 10 days or longer.

Animals↗

PubMed1996

Sulfur amino acid requirement and cystine replacement value of broiler chicks during the period three to six weeks posthatching.

Three experiments were conducted with commercial broiler chicks to determine the SAA requirement during the growth period 3 to 6 wk posthatching. A 20% CP corn-peanut meal basal diet (3,200 kcal ME(n)/kg) was analyzed to contain 0.23% Met and 0.28% cystine. True digestibility assessment in cecectomized cockerels revealed that Met and cystine in the basal diet were 81 and 75% digestible, respectively. Therefore, the basal diet contained 0.19% digestible Met and 0.21% digestible cystine. When fully fortified with DL-Met, growth rate and feed efficiency of chicks fed the corn-peanut meal diet were equal to that of chicks fed a 20% CP Met-fortified corn-soybean meal diet. In the SAA requirement assay, Ross x Hubbard male chicks were fed graded increments of DL-Met (0.03%) and L-cystine (0.03%) to achieve digestible SAA concentrations of 0.40, 0.46, 0.52, 0.58, 0.64, and 0.70%. Weight gain and feed efficiency responded quadratically (P < 0.01) to increasing doses of SAA. The estimated requirement for maximal feed efficiency was higher than that for maximal weight gain. Both visual appraisal and curve fitting procedures suggested a requirement of close to 0.61% digestible SAA. When extrapolated to a corn-soybean meal diet where SAA true digestibility is 87.5%, the total SAA requirement calculates to be 0.70% of the diet. However, because commercial corn-soybean meal diets typically contain supplemental Met, which is only 81% efficient (wt:wt) in furnishing cystine, the estimated total SAA requirement for chicks fed 20% CP Met-fortified corn-soybean meal diets with 3,200 kcal of ME/kg would probably approximately 0.72% of the diet. A DL-Met vs L-cystine supplementation assay suggested that digestible cystine can supply no more than 52% of the total requirement for digestible SAA of chicks during the 3- to 6-wk growth period.

Amino Acids, Sulfur↗

PubMed2001

Effects of conjugated linoleic acid on growth performance, feed conversion efficiency, and subsequent carcass quality in broiler chickens.

The effect of dietary conjugated linoleic acid isomers (CLA) on growth performance, carcass composition, fatty acid composition of adipose and muscle tissues, and serum lipoproteins was investigated in broiler chickens. A total of 160 (eighty male and eighty female) chickens were allocated to four dietary treatments (0.0, 0.5, 1.0, and 1.5 % CLA) and fed a standard starter diet from 8 to 21 d, and a grower-finisher diet from 22-42 d. When determined for the total period 8-42 d, feed intake and body weight gains of broiler chickens were significantly reduced (from 3.31 to 3.12 kg and from 1615 to 1435 g respectively; P < 0.05), particularly at the 1.5 % dietary CLA level. Feed conversion efficiency and carcass yield values showed no significant effects of dietary CLA. Abdominal fat deposition was significantly reduced (from 2.68 to 1.78 %; P < 0.05), the relative proportion of breast muscles was unaffected, and that of leg muscles significantly increased (from 19.0 to 20.6 %; P < 0.05). The concentration of CLA isomers (% of total methyl esters of fatty acids) increased linearly in tissue samples from broilers fed 0.5, 1.0, and 1.5 % dietary CLA. The relative proportions of saturated fatty acids (16:0, 18:0) were significantly (P < 0.01) increased, and those of monounsaturated (16:1, 18:1) and polyunsaturated fatty acids (18:2, 20:4 in muscle tissues) significantly (P < 0.05) reduced. Total serum cholesterol concentrations reached a maximum in broilers fed 1.0 % CLA and then decreased slightly (from 141.73 to 136.47 mg/dl; P < 0.01). The same was true also for HDL-cholesterol (from 113.58 to 109.97 mg/dl; The HDL cholesterol:total cholesterol ratio and serum triacylglycerol concentration was unaffected. In conclusion, feeding CLA to broiler chickens resulted in substantial incorporation of CLA isomers into their tissue lipids, thus providing a potential CLA-rich source for human consumption.

Abdomen↗

PubMed1992

Growth and tissue lipid deposition of broilers fed alpha-ketoisocaproic acid.

Dietary alpha-ketoisocaproic acid (KIC) was studied for effects on growth, feed efficiency, tissue cholesterol (TC) content, and immune response to a Newcastle disease virus (NDV) vaccination in broilers. In two experiments, broiler chicks were fed diets supplemented with graded levels of KIC to .54% of the diet. Feed efficiency, fat deposition, BW gain, and plasma cholesterol levels were determined at 3 wk. In a third experiment, broilers were fed diets supplemented with 0, .1, .2, and .4% KIC throughout the starter (0 to 3 wk), grower (3 to 6 wk), and finisher (6 to 7 wk) periods. Abdominal fat and plasma and breast TC were measured at 7 wk. In Experiment 4, levels of KIC to .6% were fed to broilers to determine TC content and to measure the immune response to NDV vaccination. Feed efficiency, BW gain, and percentage abdominal fat were not affected by KIC in any of the broiler experiments. The addition of KIC to broiler diets resulted in a significant reduction in breast (Pectoralis major) TC. Biceps (Biceps femoralis) TC, adductor (Pubo-ishio-femoralis) TC, and plasma cholesterol content was not affected by KIC. Geometric mean titers to NDV were not improved by KIC. The data indicate that KIC has no effect on growth or abdominal fat deposition, but may have a role in TC homeostasis.

Adipose Tissue↗

PubMed2004

Preweaning efficiency for mature cows of breed crosses from tropically adapted Bos indicus and Bos taurus and unadapted Bos taurus breeds.

Production data were collected on mature cows produced by mating Angus and Hereford (pooled AH), Brahman (Bh) and Boran (Br), and Tuli, a tropically adapted Bos taurus, sires by AI or natural service to Angus and Hereford cows. These cows were mated to Charolais bulls for the purpose of this study. Within each sire breed of cow, cows were assigned randomly to one of three feeding rates, 49 or 76 g of DMI/ BW0.75 or ad libitum (10 to 12 cows/feeding rate group), with weekly individual animal feed consumption recorded. Lactation yields were recorded via the weigh-suckle-weigh protocol at approximately 14, 28, 56, 84, 112, 140, 168, and 196 d postpartum for each cow/calf pair. Means for milk yield at peak lactation, total milk yields, calf birth weight, age-adjusted weaning weights, preweaning daily gain, and feed efficiency were estimated. Peak yield (kg/d) for Bh (10.3 +/- 0.36) was greater (P < 0.05) than for Tuli (9.0 +/- 0.31). Total yield (kg, 212 d) for Bh (1802 +/- 68) was greater (P < 0.05) than for Tuli (1532 +/- 59). Birth weight of AH (44 +/- 0.9) was heavier than for Bh and Br (P < 0.05). Preweaning daily calf gain (g/d) and adjusted weaning weight (kg) of Bh (813 +/- 28, 212 +/- 6.1) and Br (766 +/- 24, 202 +/- 5.1) differed (P < 0.05) from AH (589 +/- 24, 169 +/- 5.2) and Tuli (634 +/- 24, 176 +/- 5.3). Efficiency estimates (grams of adjusted weaning weight/kilograms DMI of the cow) for Bh (88 +/- 2.5) and Br (85 +/- 2.1) exceeded (P < 0.05) those for Tuli (74 +/- 2.1) and AH (73 +/- 2.1). Bos indicus breed crosses exhibited greater peak and total yield, lower birth weight, greater daily gain and adjusted weaning weight, and higher feed efficiency than did Bos taurus breed crosses (P < 0.05). Total yield, daily gain, adjusted weaning weight, and feed efficiency were higher (P < 0.05) for cows sired by bulls from tropically adapted breeds, and the peak yield was less (P < 0.10). Tuli exhibited lower total yield and birth weight than did Angus/Hereford (P < 0.05). The efficiency of crossbred Tuli cows did not differ from Angus/Hereford F1 females, but neither equaled the efficiency of crossbred cows produced using Bos indicus breeds.

Adaptation, Physiological↗

PubMed2001

Air velocity alters broiler performance under harsh environmental conditions.

The effect of air velocity (AV) on weight gain, feed intake, and feed efficiency was studied in male broiler chickens exposed to a constant 35 C, 60% RH, and continuous illumination from 4 through 7 wk of age. In two separate trials, AV of 0.5, 1.5, 2.0, and 3.0 m/s (Trial 1) and 1.0, 1.5, 2.0, and 2.5 m/s (Trial 2) were used. The fifth week was used for acclimation to the targeted environmental conditions. Weight gain was significantly higher in broilers exposed to AV of 1.5 and 2.0 m/s in both trials, which coincided with significantly higher feed intake and feed efficiency. Exposure to the low AV (0.5 and 1.0 m/s) resulted in weight gain, feed intake, and feed efficiency that were less than those of broilers exposed to high AV (2.5 and 3.0 m/s). In all treatments, broilers developed hyperthermia, but there were no significant differences in body temperature (Tb) among the birds. It can be concluded that AV has a significant effect on broiler performance; the optimal AV was found to be 1.5 to 2.0 m/s.

Air Movements↗

PubMed1976

Effect of dietary methionine status on response of chicks to coccidial infection.

Three experiments determined if the methionine requirement of broiler chicks was affected by coccidial infection. Chicks were fed a corn-soy or a corn-soy-pea basal diet containing 0.73% and 0.62% total sulfur amino acids (TSAA), respectively. Levels of 0 to 0.45% DL-methionine were added, with and without 0.01% monensin sodium. In two experiments, the chicks were inoculated at two weeks of age with a mixture of oocysts of E. acervulina, E. maxima, E. tenella, E. necatrix and E. brunetti. Lesion scores on the intestines and ceca, and blood carotenoid levels were determined at three weeks. The experiments were terminated at four weeks. A level of methionine greater than 0.47% and of TSAA greater than 0.83% was necessary to obtain maximum growth rate in uninoculated chicks. No evidence of dermatitis was observed. Growth rate and feed efficiency of chicks infected with coccidiosis were more severly depressed when the diet was not supplemented with methionine. Infections of coccidia and low levels of methionine, which in themselves did not produce any significant change in weight gain, did give a significant weight depression in combination. Adding monensin to the diet prevented a reduction in growth rate and feed efficiency of inoculated chicks fed adequate methionine. Monensin did not completely prevent the adverse effects of a coccidial infection, based on feed efficiency, when chicks were fed diets inadequate in methionine. Blood carotenoid levels were not affected by methionine level, but were significantly lowered by coccidial infection in the absence of monensin. Intestinal and cecal lesions in inoculated chicks were significantly reduced by including monesin in the diet. Although the coccidial infection more severly affected the performance of chicks fed diets deficient in methionine, satistical analysis of pooled data indicated no difference in the quantitative requirement of chicks for methionine. Therefore, a level of methionine and cystine adequate for optimum growth under the coccidial-free conditions should be adequate for chicks when infected with coccidia.

Animals↗

PubMed1999

Evaluation of sodium bicarbonate, chloride, or sulfate with a coccidiostat in corn-soy or corn-soy-meat diets for broiler chickens.

During the period from January to June, combined-sex broiler chickens were inoculated with coccidia via drinking water at 14 d of age. In a completely randomized design (eight replicate pens; 88 chicks per pen) using built-up litter, experimental diets contained monensin plus 0.20% dietary sodium bicarbonate (SBC), which provided 0.054% sodium and 0.144% bicarbonate. Treatment with SBC significantly improved coccidial lesion score, 45-d body weight, and feed efficiency compared with monensin alone. In a 2 x 5 factorial trial using built-up litter pens (eight replicate pens; 88 chicks per pen) vs. each ionophore alone, 0.20% dietary SBC with monensin significantly improved body weight, uniformity, and feed efficiency; 0.20% SBC with halifuginone, lasalocid, monensin, or salinomycin significantly reduced mortality; and 0.20% SBC with lasalocid, monensin, or salinomycin significantly increased breast meat yield. In a 2x4 factorial trial (12 replicate pens; 88 chicks per pen) on built-up litter, corn-soy and corn-soy-meat diets (higher potassium, lower chloride) with monensin were evaluated using 0.054% sodium from SBC, NaCl, or sodium sulfate decahydrate (SSD). With both diet types, SBC (0.20%) or NaCl (0.139% extra) significantly improved weight uniformity, feed efficiency, mortality, and breast meat yield; however, the SSD results were closer to controls. In a 21-d battery brooder test using similar diets and design (2x4 factorial; 4 replicate pens; 10 chicks per pen), SBC and NaCl significantly reduced coccidial lesion scores; SSD produced a significant, but weaker effect. Extra NaCl significantly increased water intake (approximately 37%), water excretion (approximately 27%), and litter moisture (approximately 22%) with both diet types. The SSD did not affect water intake.

Animal Feed↗