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The effect of dietary protein and fermentable carbohydrates levels on growth performance and intestinal characteristics in newly weaned piglets.

Reducing the CP content and increasing the fermentable carbohydrates (FC) content of the diet may counteract the negative effects of protein fermentation in newly weaned piglets fed high-CP diets. To study the synergistic effects of CP and FC on gut health and its consequences for growth performance, 272 newly weaned piglets (26 d of age, 8.7 kg of BW) were allotted to 1 of 4 dietary treatments in a 2 x 2 factorial arrangement, with low and high CP and low and high FC content as the factors. Eight piglets from each dietary treatment were killed on d 7 postweaning. Feces and digesta from ileum and colon were collected to determine nutrient digestibility, fermentation products, and microbial counts. In addition, jejunum tissues samples were collected for intestinal morphology and enzyme activity determination. During the entire 4-wk period, interactions between the dietary CP and FC contents were found for ADFI (P = 0.022), ADG (P = 0.001), and G:F (P = 0.033). The high-FC content reduced ADFI, ADG, and G:F in the low-CP diet, whereas the FC content did not affect growth performance in the high-CP diet. Lowering the CP content of the low-FC diet improved ADFI and ADG, whereas lowering the CP content of the high-FC diet did not influence growth performance. The low-CP diets resulted in a lower concentration of ammonia in the small intestine (P = 0.003), indicating reduced protein fermentation. In the small intestine, the high FC content increased the number of lactobacilli (P = 0.047), tended to decrease the number of coliforms (P = 0.063), tended to increase the lactic acid content (P = 0.080), and reduced the concentration of ammonia (P = 0.049). In the colon, the high-FC diets increased the concentration of total VFA (P = 0.009), acetic acid (P = 0.003), and butyric acid (P = 0.018), and tended to decrease the ammonia concentration (P = 0.076). Intestinal morphology and activity of brush border enzymes were not affected by the diet, although maltase activity tended to decrease with increasing dietary FC (P = 0.061). We concluded that an increase in the dietary FC content, and to a lesser extent a decrease in the CP content, reduced ammonia concentrations and altered the microflora and fermentation patterns in the gastrointestinal tract of weaned piglets. However, these effects were not necessarily reflected by an increased growth performance of the piglets.

Animal Feed↗

Influence of dietary non-essential amino acid profile on growth performance and amino acid metabolism of Nile tilapia, Oreochromis niloticus (L.).

The quality of dietary protein is an important factor influencing the growth performance of fish. To evaluate the quality of protein, the variables commonly studied are the composition of the essential amino acids, the digestibility and the protein use efficiency. The goal of the present experiment was to test the effect of the dietary non-essential amino acid composition on the growth of Nile tilapia (Oreochromis niloticus). The fish were fed three purified diets differing only in their non-essential amino acid composition. The influence of the experimental diets on the growth performance, on the activity of enzymes involved in the amino acid metabolism, aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT), and on whole body delta(15)N values was investigated. Body mass, lipid, protein and energy gain differed significantly between the feeding groups. The activity of ASAT in the whole liver was significantly higher in fish with a positive protein balance compared to fish which lost protein. Whole body delta(15)N values of fish were negatively correlated with their body mass gain. Despite the poor utilisation of synthetic amino acids, the experiment indicates the importance of the dietary non-essential amino acid composition for the growth performance of fish. The study reveals the possibility to trace the utilisation of synthetic amino acids by determining the isotopic composition of dietary amino acids and tissues or whole bodies of animals.

Alanine Transaminase↗

Growth performance and enzyme development in weanling pigs injected with dexamethasone.

Three experiments were conducted to evaluate the effects of dexamethasone (DEX) on growth performance and on selected digestive enzyme activities in weanling pigs. In Exp. 1, 96 pigs (6.7 kg BW and 27 d) were used in a 3 x 2 factorial combination of three DEX frequencies (no injection; 1 mg DEX/kg BW 3 d before weaning; and 1 mg DEX/kg BW 6 and 3 d before weaning) and two feeding regimens: a simple diet fed throughout the 28-d trial, or a semicomplex diet fed during the first 14 d postweaning, followed by the simple diet. Growth performance was not affected (P > .10) by hormonal treatment. Pigs fed the simple diet had a greater ADF1 after d 15 postweaning (P < .10) and higher ADG from 15 to 21 d postweaning (P < .01). In Exp. 2, 80 pigs (7.2 kg BW and 26 d) were assigned 3 d before weaning to four dosages of DEX (0, .33, .66, and .99 mg/kg BW). Growth performance was similar regardless of DEX dosing. In Exp. 3, 24 pigs (6.4 kg BW and 21 d) were injected with DEX (1 mg/kg BW) or saline solution on d 3 before weaning. Four pigs per treatment were slaughtered at weaning, or on d 3 and d 6 postweaning. Dexamethasone resulted in greater (P < .10) pancreas weight and increased (P < .01) total activity of amylase and sucrase, but lactase was lowered (P < .10). Dexamethasone injection enhanced digestive enzyme activity but failed to improve performance, presumably because of the reduced feed intake of pigs at weaning.

Aging↗

Escherichia coli phytase improves growth performance of starter, grower, and finisher pigs fed phosphorus-deficient diets.

Corn-soybean meal-based diets, consisting of a high-P control (HPC) containing supplemental dicalcium phosphate (DCP), a basal diet containing no DCP, and the basal diet plus Escherichia coli phytase at 500 or 1,000 phytase units per kilogram (FTU/kg; as-fed basis) were fed to evaluate growth performance in starter, grower, and finisher pigs. Pigs were blocked by weight and gender, such that average weight across treatments was similar, with equal numbers of barrows and gilts receiving each treatment in each block. In Exp. 1, 48 pigs with an average initial BW of 11 kg, housed individually, with 12 pens per diet, were used to evaluate growth performance over 3 wk. Overall ADG and G:F were increased linearly (P < 0.05) by dietary phytase addition. Final BW and plasma P concentrations at 3 wk also increased linearly (P < 0.05). In Exp. 2, 128 pigs with an average initial BW of 23 kg, housed four pigs per pen, with eight pens per diet, were used to evaluate growth performance over 6 wk. A linear increase in response to phytase was noted for ADG and G:F in all three 2-wk periods, as well as overall (P < 0.05). Percentage of bone ash also showed a linear increase (P < 0.01). In Exp. 3, 160 pigs (53 kg), housed five pigs per pen, with eight pens per diet, were used to evaluate growth performance over 6 wk. A linear increase was detected for final BW, as well as ADG and G:F in the first and second 2-wk periods, and overall (P < 0.01). Twenty-four 15-kg individually housed pigs were used to evaluate total-tract nutrient digestibility in Exp. 4. Daily absorption of P linearly increased (P < 0.05) with phytase supplementation. Results of this research indicate that E. coli phytase is effective in liberating phytate P for uptake and utilization by starter, grower, and finisher pigs.

6-Phytase↗

Effects of modified tall oil and creatine monohydrate on growth performance, carcass characteristics, and meat quality of growing-finishing pigs.

The effects of feeding modified tall oil (MTO) and creatine monohydrate (CMH) on growing-finishing pig growth performance, carcass characteristics, and meat quality were determined. Eighty cross-bred barrows (initially 45.4 kg) were allotted randomly to one of four dietary treatments by weight and ancestry. The experiment was arranged as a 2 x 2 factorial with two levels of MTO (0 or 0.50%), which were fed throughout the growing-finishing period, and two levels of CMH (0 or 25 g/d), which were fed for the final 10 d before slaughter. The corn-soybean meal diets were fed in two phases (45.4 to 78.9 kg and 78.9 to 117.5 kg BW). When CMH was added to the diet in place of corn, average BW was 107.5 kg. Feeding MTO increased (P < 0.05) ADG and gain:feed ratio (G/F) during the 45.4- to 78.9-kg growth interval and tended to improve (P = 0.10) G/F during the 45.4- to 107.5-kg growth interval. Dietary treatment did not affect (P > 0.15) growth performance during the 78.9- to 107.5-kg growth interval. Modified tall oil increased (P = 0.02) G/F during the 10-d CMH supplementation period, and CMH numerically (P = 0.11) increased ADG and G/F. Supplementation of CMH did not affect (P > 0.20) any measured carcass characteristic or measures of meat quality at 24 h or 14 d postmortem. Feeding MTO reduced average back-fat (P = 0.05) and 10th rib backfat (P = 0.01) but did not affect (P > 0.10) other measured carcass characteristics or measures of meat quality at 24 h postmortem. Modified tall oil increased (P = 0.02) L* values (lightness) and tended to increase (P < 0.10) thawing and cooking losses of longissimus muscle chops at 14 d postmortem. These data demonstrate that MTO improves growth performance and reduces backfat in growing-finishing pigs, but supplementation of CMH, under the conditions of this experiment, was not beneficial for growing-finishing pigs.

Animal Feed↗

Intermittent light and growth performance of male turkeys from 2 to 22 weeks of age.

Growth performance of tom turkeys under intermittent lighting was examined. Light treatments were given from 2 to 22 weeks of age and consisted of a control group maintained on 23L:1D and three intermittent lighting regimens: IL:3D repeated 6 times daily, .25L:.75D repeated 24 times daily, and 3L:11D:3L:7D repeated daily. Body weight, feed consumption, feed conversion, mortality, and leg abnormalities were recorded. Body weights of control toms at 18 and 22 weeks of age were significantly smaller than those of each of the intermittent light treatment groups. Weight differences ranged from .7 to 1.3 kg. Body weights among the three intermittent light treatments were similar. Although feed conversions at all five measurement periods were numerically better in all of the intermittent light treatment groups than the control group, differences were not significantly different at and beyond 14 weeks of age. Likewise, no significant differences in mortality or leg disorders occurred among the light treatment groups during the study. The results of this study indicate that tom market turkeys can have a better growth performance, along with a savings in electricity used for lighting, when raised under intermittent lighting rather than under a single, continuous photoperiod of 23 hr/day.

Animals↗

Effect of trimethylamine oxide and betaine in swine diets on growth performance, carcass characteristics, nutrient digestibility, and sensory quality of pork.

Two growth experiments and one digestibility experiment were conducted to study the effect of trimethylamine oxide (TMAO) and betaine in swine diets. In Exp. 1, 36 limit-fed pigs averaging 19.1 kg in initial weight were used to study the effect of adding TMAO at 10 g/kg of feed or betaine at an equivalent level of methyl groups (10.5 g/kg feed) to a high-fat (11.3% ether extract) basal diet. Dietary addition of TMAO increased ADG by 61 g/d, reduced number of days to market by 8.3 d (P<.02), and tended (P<.09) to improve gain/feed (G/F) compared with the control diet. Betaine had no effect on growth performance of pigs. Adding TMAO or betaine to diets had no effect on percent carcass fat, percent carcass lean, or dressing percentage. Dietary supplementation of TMAO reduced (P<.05) plasma triacylglycerol level (TAG) compared with the control diet. There was no effect of dietary TMAO or betaine on sensory quality characteristics of pork. In Exp. 2, 48 ad libitum-fed pigs averaging 21.7 kg initial BW and 104.7 kg final BW were used to determine the effect of adding low and intermediate levels of TMAO (1, 2, or 5 g/kg) to diets. Adding 1 g of TMAO increased G/F (P<.01) compared with control pigs. When using orthogonal contrasts, adding 2 g of TMAO reduced (P<.05) P2 backfat thickness and tended to increase (P<.09) lean percentage compared with the control diet. Trimethylamine oxide gave a quadratic effect (P<.05) on plasma TAG levels. Adding 1 and 2 g of TMAO increased plasma TAG, but 5 g of TMAO decreased it compared with the control diet. In Exp. 3, 12 barrows of 42.3 kg average initial BW and 50.0 kg final BW were used to investigate the effect of supplementing diets with 1 g of TMAO and 1.27 g of betaine/kg of feed on apparent total tract nutrient digestibility. The addition of TMAO increased (P<0.03) apparent total tract digestibility of fat (HCl-EE). Betaine had no such effect. Adding TMAO to diets influenced growth performance and carcass quality in a dose-dependent manner.

Animal Feed↗

Impact of phase-feeding on the growth performance of broilers subjected to high environmental temperatures.

Experiments were conducted to evaluate the effects of phase feeding (PF) on broilers subjected to heat stress during the grower and finisher periods. Birds were fed diets containing lysine, sulfur amino acid (SAA), or threonine levels based on NRC (1994) recommendations or predictions from linear regression equations (PF). With PF, diets were switched every other day, resulting in steadily decreasing lysine, SAA, and threonine levels. In Experiment 1 (42 to 56 d), growth performance was unaffected (P > 0.05) by diet, and cost per kilogram of weight gain did not differ (P > 0.05) between treatments. In Experiments 2 (23 to 42 d) and 3 (42 to 63 d) birds were housed in environmental chambers and subjected to high (15 h at 35 C, 9 h at 23.9 C) or normal (23.9 C) temperatures. In both experiments, heat stress reduced (P < 0.05) growth performance and increased (P < 0.05) percentage leg yield. Moreover, heat stress decreased percentage breast yield (P < 0.05) in Experiment 2. Growth performance and carcass yield were unaffected (P > 0.05) by PF relative to birds fed NRC-based diets, with the exception of feed efficiency, which was reduced (P < 0.05) by PF under normal temperatures in Experiment 2. Data indicated that dietary lysine, SAA, and threonine levels may be reduced every other day under a PF program without adversely affecting growth performance or carcass yield of birds exposed to high environmental temperatures. Cost analysis indicated that savings might be available with PF under high temperature conditions.

Amino Acids, Sulfur↗

Effect of dietary L-carnitine on growth performance and body composition in nursery and growing-finishing pigs.

Two experiments were conducted to determine the effect of dietary L-carnitine on growth performance and carcass composition of nursery and growing-finishing pigs. In Exp. 1,216 weanling pigs (initially 4.9 kg and 19 to 23 d of age) were used in a 35-d growth trial. Pigs were blocked by weight in a randomized complete block design (six pigs per pen and six pens per treatment). Four barrows and four gilts were used to determine initial carcass composition. L-Carnitine replaced ground corn in the control diets to provide 250, 500, 750, 1,000, or 1,250 ppm. On d 35, three barrows and three gilts per treatment (one pig/block) were killed to provide carcass compositions. L-Carnitine had no effect (P > 0.10) on growth, percentages of carcass CP and lipid, or daily protein accretion. However, daily lipid accretion tended to decrease and then return to values similar to those for control pigs (quadratic P < 0.10) with increasing dietary L-carnitine. In Exp. 2, 96 crossbred pigs (initially 34.0 kg BW) were used to investigate the effect of increasing dietary L-carnitine in growing-finishing pigs. Pigs (48 barrows and 48 gilts) were blocked by weight and sex in a randomized complete block design (two pigs/pen and eight pens/treatment). Dietary L-carnitine replaced cornstarch in the control diet to provide 25, 50, 75, 100, and 125 ppm in grower (34 to 56.7 kg; 1.0% lysine) and finisher (56.7 to 103 kg; 0.80% lysine) diets. At 103 kg, one pig/pen was slaughtered, and standard carcass measurements were obtained. Dietary L-carnitine did not influence growth performance (P > 0.10). However, increasing dietary carnitine decreased average and tenth-rib back-fat (quadratic, P < 0.10 and 0.05), and increased percentage lean and daily CP accretion rate (quadratic, P < 0.05). Break point analysis projected the optimal dosage to be between 49 and 64 ppm of L-carnitine for these carcass traits. It is concluded that dietary carnitine fed during the nursery or growing-finishing phase had no effect on growth performance; however, feeding 49 to 64 ppm of L-carnitine during the growing-finishing phase increased CP accretion and decreased tenth-rib backfat.

Animals↗

Effects of L-carnitine administration on growth performance, carcass traits, blood serum parameters and abdominal fatty acid composition of ducks.

Effects of L-carnitine administration via drinking water on growth performance, carcass traits, blood serum parameters and abdominal fatty acid composition of ducks was examined. One hundred day-old Turkish native duck chicks were divided into two groups, each with five replicates and given the same diets with 0 and 200 mg/l carnitine chlorhydrate via drinking water. The study lasted 8 weeks, with the first 4 weeks as a starter and the last 4 weeks as grower period. At the end of the study five ducks were randomly selected from each subgroup for slaughter. Growth performance parameters of ducks were not affected significantly by L-carnitine administration. Live weight, daily weight gain, cumulative feed consumption and average feed conversion efficiency were found to be 1490 and 1621 g, 26.0 and 28.1 g, 5386 and 5662 g, 3.75 and 3.54 kg/kg in the control and in the carnitine groups respectively. L-carnitine administration did not effect carcass traits and serum cholesterol, total lipid, triglyceride and glucose levels. Total saturated fatty acid content of abdominal fat significantly decreased, mono- and polyunsaturated fatty acid content were not affected by L-carnitine administration. In conclusion, L-carnitine administration by drinking water did not affect growth performance, carcass traits and blood parameters in ducks.

Adipose Tissue↗

Effects of tea saponins on in vitro ruminal fermentation and growth performance in growing Boer goat.

Two experiments were conducted to investigate the effects of tea saponins (TS) on in vitro ruminal fermentation and growth performance in growing Boer goats. In Experiment 1, the Reading Pressure Technique (RPT) system was used to investigate the effect of addition of TS (0, 0.2, 0.4 and 0.8 mg/ml) on the ruminal fermentation in vitro. The 24h gas production and methane emission were significantly decreased when 0.4 or 0.8mg TS was included, suggesting that the TS could inhibit the release of methane. Compared to the control, the TS had little effect on pH values and the concentration of total volatile fatty acids in the ruminal fluids. However, the fermentation patterns were changed, with lower acetate and higher proportions of propionate when TS was added. Ammonia-N concentration and protozoal counts were significantly reduced, while microbial protein yield was increased by the TS addition, suggesting that the TS could modify the ruminal fermentation. In Experiment 2, 27 growing Boer goats were used to evaluate the effects of the TS addition on growth performance. The animals received the same basal diets, and added TS at levels of 0 (C), 3 g (T1) and 6 g (T2) per day. The experiment lasted for 60 days with the first 15 days for adaptation. Blood samples were obtained by jugular venipuncture before the morning feeding on the final day of the experiment. During the whole periods, dry matter intake, average daily gain and feed efficiency in T1 were higher than in the other two. Serum total protein, albumin, high density lipoprotein cholesterol, Ca and P and alkaline phosphatase levels were higher in group T1 than in C and T2, whereas the blood urea nitrogen, creatinine and total cholesterol were lower in the TS-added groups. The concentrations of glucose, glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase were not affected by the TS. From the results obtained in this study, it is inferred that the TS could modify the ruminal fermentation and that proper doses of TS may have potential in improving the animal growth performance, whereas at high doses, it may have adverse effects on animal production.

Animals↗

Effect of benzoic acid on growth performance, nutrient digestibility, nitrogen balance, gastrointestinal microflora and parameters of microbial metabolism in piglets.

In order to investigate the effects of benzoic acid on growth performance, nutrient digestibility, nitrogen balance and gastrointestinal microflora of piglets, we conducted a performance experiment and a separate balance study. The performance experiment involved four different dietary treatments: (1) basal diet (negative control); (2) basal diet supplemented with benzoic acid at 5 g/kg; (3) basal diet supplemented with benzoic acid at 10 g/kg; (4) basal diet supplemented with potassium diformate at 12 g/kg. Each dietary treatment was assigned to nine replicate groups, each consisting of two piglets. Live weight, daily weight gain, feed intake and feed conversion ratio were monitored as performance parameters over a 35-day period. Supplementation of the diet with benzoic acid resulted in a dose-dependent increase in feed intake and body weight gain and an improved feed conversion ratio. Piglets fed the diet supplemented with benzoic acid at 10 g/kg outperformed the control piglets in mean feed intake, body weight gain and feed conversion ratio by 9%, 15% and 6% respectively. Growth performance of the piglets fed the diet with benzoic acid at 10 g/kg was similar to that of piglets fed the diet supplemented with potassium diformate. In the balance experiment three groups of six piglets each were fed either a control diet or diets supplemented with benzoic acid at 5 or 10 g/kg respectively. Benzoic acid did not significantly affect nutrient digestibility but increased nitrogen retention. Piglets fed the diets supplemented with benzoic acid at 5 or 10 g/kg retained 5% and 6% more nitrogen, respectively, than control piglets. Supplementation of benzoic acid did not influence the pH value or the concentration of ammonia in the gastrointestinal tract but reduced the number of bacteria in the digesta. In the stomach the number of total aerobic, total anaerobic, lactic acid forming and gram-negative bacteria was reduced; in the duodenum the presence of benzoic acid reduced the number of gram-negative bacteria and in the ileum the number of total aerobic bacteria in a dose-dependent manner. Benzoic acid also considerably reduced the concentration of acetic acid in the duodenum. In conclusion, the data of this study suggest that benzoic acid exerts strong antimicrobial effects in the gastrointestinal tract of piglets and therefore enhances growth performance and nitrogen retention.

Animal Feed↗

Association of growth performance with atrophic rhinitis and pneumonia detected at slaughter in a conventional pig herd in Hungary.

The influence of atrophic rhinitis (AR) and pneumonia on growth performance was assessed in a conventional farrow-to-finish pig farm affected by both diseases. All tested pigs (n = 138) were individually weighed at birth, at weaning, at moving to the growing/finishing unit, and at slaughtering. The extent (grade) of turbinate atrophy and lung consolidation attributable to pneumonia was determined in each pig at slaughter. A negative correlation was found between birth weight and the prevalence of nasal lesions at slaughter, suggesting that pigs born with smaller weight may be more susceptible to AR. The growth performance of the pigs also showed a negative correlation with the degree of turbinate atrophy. In the nursery period, the average daily gain (ADG) of pigs with moderate/severe turbinate atrophy was 13.3% lower than that of animals with healthy snouts. In the finishing period, pigs with mild AR lesions had an ADG reduction of 6.2%, while pigs with severe AR lesions had a significant, 9.4% reduction in ADG as compared to the AR-free pigs. The extent of weight gain reduction over the whole life cycle was very similar (approximately 6%) in the pigs having either AR or pneumonia alone. In those pigs where both respiratory diseases were present, their effects seemed to be added up (11.5%); however, nasal lesion scores and percentage of lung consolidation did not show statistically apparent interactive effects on growth performance.

Animals↗

Prior or concurrent exposure to different species of avian Eimeria: effect on sporozoite invasion and chick growth performance.

The effects of prior (immunity) or concurrent administration of Eimeria acervulina or Eimeria tenella on cellular invasion in vivo and in vitro and on growth performance in white leghorn chickens (WLC) were examined. Weight gains of WLC immunized with E. acervulina and challenged with E. tenella were significantly greater than those of nonimmunized chicks challenged with E. tenella (this occurred despite the increased invasion by E. tenella in E. acervulina-immunized chicks that was reported earlier). The weight gains and modest but consistent improvements in intestinal lesion scores, feed conversion ratios, and oocyst shedding in immunized/challenged WLC indicated that E. acervulina conferred a small measure of protection against E. tenella infection that was independent of the effect on invasion. In contrast, immunization of WLC with E. tenella significantly decreased (41%-51%) invasion by E. acervulina as compared with that in nonimmunized WLC but had little effect on chick growth performance. Concurrent inoculation of chicks with E. tenella and E. acervulina had little effect on invasion by E. tenella sporozoites or on subsequent performance of the chicks. In vitro, prior exposure of cultured cells to either of two isolates of E. tenella also caused a significant decrease in invasion by E. acervulina. No gross changes occurred in the culture morphology between the E. tenella-inoculated and noninoculated cultures. Collectively, the data indicate that prior exposure of WLC and cultured cells to single isolates of avian coccidia markedly influenced invasion by other species but had less effect on the growth performance of the birds.

Animals↗

Dietary chromium supplementation with or without somatotropin treatment alters serum hormones and metabolites in growing pigs without affecting growth performance.

Twenty-four castrated male pigs were used in a 2 x 2 treatment array to determine the main effects of and interactions between dietary chromium supplementation and pituitary porcine somatotropin (ppST) administration on growth performance and serum hormone and metabolite concentrations. The treatments were 1) control (basal diet); 2) chromium (basal diet+300 micrograms/kg diet added trivalent chromium as chromium picolinate); 3) ppST (100 micrograms/(kg body wt.d); and 4) chromium+ppST. Treatments were administered when pigs weighed between 30 and 60 kg. Blood was collected when pigs weighted 45 and 60 kg. All pigs treated with ppST exhibited improvements in growth performance (P < 0.05). Pigs given chromium showed no improvements in growth rate, feed efficiency or composition of gain. Measurements at 60 kg body weight revealed that ppST increased the cholesterol:HDL cholesterol ratio (P < 0.05). Chromium lowered serum insulin and glucose concentrations relative to controls (P < 0.05) and normalized the increase in glucose and insulin resulting from ppST treatment. No ppST x chromium interactions were noted, suggesting these changes in glucose and insulin metabolism are exerted through different mechanisms. These results indicate that chromium does not affect growth performance of young growing pigs. Chromium does normalize altered hormone and metabolite concentrations resulting from ppST treatment.

Analysis of Variance↗

The interrelationship of porcine somatotropin administration and dietary phosphorus on growth performance and bone properties in developing gilts.

Seventy-two gilts (initial weight = 57.9 kg) were used to determine the interrelationship of porcine somatotropin (pST) administration and dietary P on growth performance of finishing gilts (58 to 106 kg) and the effect on bone mechanical properties and mineralization for a 35-d postfinishing phase after withdrawal of pST administration. Gilts were injected daily with placebo (control) or 4 mg of pST and fed .4, .6, or .8% P in the finishing phase. Administration of pST increased ADG and G/F (P < .01) and decreased ADFI (P < .01) during the finishing phase. Increasing dietary P resulted in increased (quadratic, P < .04) ADG from d 0 to 28 of the finishing phase; however, dietary P had no effect (P > .18) on ADG, G/F, or ADFI for the overall finishing phase. When each block weight averaged 106 kg, half the gilts were slaughtered and the first rib, femur, and third and fourth metacarpals were collected. Stress, modulus of elasticity, and ash content of rib, femur, and metacarpals were reduced (P < .06) and femur wall thickness was increased (P < .01) in pST-treated gilts. Increasing dietary P increased (linear, P < .05) bending moment, stress, and ash content for all bones collected, with the exception of metacarpal stress, which was not affected (P > .22). The remaining 36 gilts were individually fed 1.8 kg/d of a common diet to assure a P intake of 22.8 g/d for the 35-d postfinishing phase. Gilts that received higher levels of dietary P during the finishing phase had increased (linear, P < .06) bending moment and ash content for the rib and femur; rib stress, and femur wall thickness were also increased after the postfinishing phase. From d 0 to 28 of the finishing phase, pST-treated gilts required a diet with > .4% P (10.3 g/d P) to maximize growth performance. However, a diet with .4% P (12.44 and 10.66 g/d P, control and pST-treated, respectively) was adequate for growth performance during the overall finishing phase (56 to 106 kg).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Effect of carbonated water on growth performance of cockerels subjected to constant and cyclic heat stress temperatures.

Three growth trials were performed to determine the effect of carbonated water on growth performance of cockerels subjected to heat stress temperatures. In Trial 1, a 2 X 2 X 2 factorial design was used to test growth performance of Columbian crossbred cockerels between 8 and 11 weeks of age. The birds were subjected to either cyclic (day-night) heat stress (H) temperature (29 to 34 C) or cyclic (day-night) moderate (M) temperature (25 to 29 C), fed either a corn soy grower (G) diet or a 20% alfalfa diet (A), and provided with tap (TW) or carbonated (CW) drinking water. In Trial 2, a 2 X 4 X 2 factorial was used to access the effect of CW on growth performance of Hubbard cockerels between 4 and 7 weeks of age. Birds were grown in the M or H cyclic thermal environments with dietary treatments consisting of A, G, A plus 1% sodium bicarbonate (AB) and G plus 1% sodium bicarbonate (GB). In Trial 3, a 2 X 2 factorial was used to test the effect of CW on growth performance of Hubbard cockerels fed the G diet and subjected to either constant heat stress (33 C) or thermoneutral (25 C) temperatures. A 24-hr photoperiod was used in each experiment. In all three trials, heat stress reduced (P less than .05) average daily gain (ADG), feed intake, and feed efficiency (G/F).(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

Effect of substitution of sugarbeet pulp for barley in diets for finishing rabbits on growth performance and on energy and nitrogen efficiency.

One hundred forty New Zealand White x California weanling rabbits were used to study the influence of increasing dietary contents of digestible fiber replacing nonstructural carbohydrates on feed efficiency and growth performance. Four diets, formulated by replacing sugarbeet pulp (SBP) for barley grain, and two slaughter weights (2 or 2.5 kg) were used in a 4 x 2 factorial arrangement. Inclusion of 15% SBP decreased dietary energy and CP digestibilities by 6% (P < .001), but nonsignificant effects were found on growth performance, empty body composition, and DE and digestible CP efficiencies for growth. Higher levels of SBP (35 and 50%) led to leaner animals and did not affect DE intake but greatly impaired (P < .001) DE and nitrogen efficiencies, NEg intake, growth rate, and dressing percentage in relation to the control diet. Inclusion of SBP increased the weight of gut contents (P < .001) and decreased cecal pH (P < .001), with no significant effect on mortality. Slaughter weight did not affect growth rate or energy efficiency but impaired (by 13%, P < .001) feed conversion rate. Higher (P < .001) energy content in live weight gain (12.5%) and dressing percentage (3.2%) were observed for rabbits slaughtered at 2.5 kg than for those slaughtered at 2 kg. Our data indicate that SBP can replace 15% of barley grain without decreasing growth performance, although energy and nitrogen efficiencies were impaired by 5%.

Animal Feed↗