virginiamycin and Weight-Gain

Two experiments were conducted to examine the influence of protein and virginiamycin (VM) supplementation on feedlot growth performance, digestion, and metabolizable AA (MAA) supply of calf-fed Holstein steers. Growth performance and dietary energetics were evaluated in 120 Holstein steers (127 ± 9 kg). During the initial 112-d feeding period, a steam-flaked corn-based diet was balanced to meet either 100% (MAB) or 87% (UREA) of MAA requirements. Diets were supplemented with or without 22.5 mg/kg VM in a 2 × 2 factorial arrangement. Subsequently (d 112 to 308), all steers received the UREA diet with or without VM. During the initial 112-d, MAB increased ADG, G:F, and dietary NE ( < 0.01). Thereafter, when all steers received the UREA diet, ADG, G:F, and dietary NE were not different ( > 0.10) across initial supplementation treatments. Overall (d 1 to 308), MAB did not affect ADG ( > 0.10) but enhanced G:F efficiency ( = 0.03) and dietary NE ( = 0.05). During the initial 112-d period and through the remainder of the experiment, VM increased G:F ( < 0.01) and dietary NE ( < 0.01). Four Holstein steers (146 ± 4 kg) with cannulas in the rumen and proximal duodenum were used in a 4 × 4 Latin square design to evaluate initial 112-d treatment effects on digestive function. There were no treatment effects ( > 0.10) on ruminal digestion of OM, NDF, starch, microbial efficiency, or total tract digestion of OM and NDF. The MAB increased indispensable AA flow to the small intestine ( < 0.01) and total tract digestion of N ( < 0.01) and starch ( = 0.04). Observed AA supply to small intestine was in agreement with expected supply ( = 0.96). Virginiamycin decreased ( = 0.04) nonammonia N flow to the small intestine and did not affect ( > 0.10) total tract N digestion. Extrapolating from AA supplies in the metabolism study, MAB satisfied indispensable AA requirements during the initial 112-d period, whereas the UREA diet met 73.5% and 79.2% of methionine and lysine requirements, respectively. During the subsequent periods (d 112 to 308) indispensable AA supplies exceeded theoretical requirements. We conclude that enhancements in energy utilization when diets are balanced to meet MAA requirements of calf-fed Holstein steers during the initial 112-d feedlot period remain appreciable throughout time on feed. Virginiamycin enhanced efficiency of energy utilization throughout the feedlot growing-finishing period.

Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Cattle; Diet; Dietary Proteins; Dietary Supplements; Digestion; Male; Nutritional Status; Protein Synthesis Inhibitors; Starch; Virginiamycin; Weight Gain

The present study aimed to investigate the effect of supplemental genistein (an isoflavonoid) on performance, lymphoid organs' development, and cellular and humoral immune responses in broiler chicks. A total of 675-day-old male broiler chicks (Ross 308) were randomly assigned to the five replicate pens (15 chicks each) of nine experimental diets. Dietary treatments included a negative (not-supplemented) control diet, two positive control groups (virginiamycin or zinc-bacitracin, 20 mg/kg), and diets containing 10, 20, 40, 80, 160 and 320 mg/kg of genistein. The cutaneous basophil hypersensivity (CBH) test was measured at day 10 of age after toe web injection with phytohemagglutinin-P. In addition, sera samples were collected after different antigen inoculations to investigate antibody responses. At day 28 of age, three randomly selected birds from each pen were euthanized to evaluate the relative weights of lymphoid organs. Results showed that dietary supplementation of both antibiotics increased (P<0.01) feed intake during 1 to 42 days of age. Furthermore, daily weight gain was influenced (P<0.01) by dietary treatments throughout the trial, so that the birds fed on antibiotics and 20 to 80 mg/kg genistein diets revealed the greater weight gains compared with other experimental groups. The best (P<0.05) feed conversion ratio assigned to the birds fed on diets containing antibiotics and moderate levels (40 to 80 mg/kg) of genistein. Although the relative weights of thymus (P<0.05) and bursa of Fabricius (P<0.01) were greater in birds fed on genistein-supplemented diets compared with antibiotics-supplemented birds, the spleen weight was not affected by experimental diets. Similarly, CBH response and antibody titers against Newcastle and infectious bronchitis disease viruses were markedly (P<0.05) greater in chicks fed on diets supplemented with 20 to 80 mg/kg of genistein. Interestingly, the higher dosages of genistein suppressed CBH and antibody responses to the levels seen by control and antibiotics chicks. Dietary inclusion of genistein increased (P<0.05) lymphocytes and subsequently reduced (P<0.01) heterophil to lymphocyte ratio. The present findings indicate that dietary genistein supplementation at the levels of 20 to 80 mg/kg not only improves growth performance, but also could beneficially affect immunological responses in broiler chicks.

Topics: Animals; Basophil Degranulation Test; Chickens; Diet; Dietary Supplements; Dose-Response Relationship, Drug; Eating; Genistein; Infectious bronchitis virus; Lymphoid Tissue; Male; Newcastle disease virus; Phytohemagglutinins; Virginiamycin; Weight Gain

An experiment was conducted to investigate the supplementation of direct-fed microbials (DFM) as an alternative to antibiotics on growth performance, immune response, cecal microbial population, and ileal morphology of broiler chickens. A total of 800 one-day-old male broiler chicks (Ross × Ross) were randomly allotted to 4 dietary treatments with 4 replicate pens per treatment (50 birds/replicate pen). The 4 dietary treatments fed for 35 d were a corn-soybean meal basal diet (control); control plus 0.1% virginiamycin, as an antibiotic growth promoter (AGP); control plus 0.1% direct-fed microbials that contained Lactobacillus reuteri (DFM 1); and control plus 0.1% direct-fed microbials that contained a mixture of L. reuteri, Bacillus subtilis, and Saccharomyces cerevisiae (DFM 2). Results showed that dietary AGP and DFM supplementation significantly increased (P < 0.05) the BW gain of broilers during 0 to 21 d. The feed intake was reduced, whereas the feed conversion was improved significantly when birds were fed DFM 2 at 0 to 7 d of age. The white blood cell and monocyte levels were significantly higher in the DFM 2 group compared with the control. In addition, feeding DFM significantly (P < 0.05) increased the plasma immunoglobulin levels where a higher level was observed in DFM 2 compared with those of the other treatments. Neither DFM nor AGP treatments affected the cecal Lactobacillus and Salmonella content; however, cecal Escherichia coli content significantly decreased in broiler chickens fed DFM and AGP. The ileal villus height, and width and total thickness of muscularis externa were significantly increased when birds were fed DFM compared with AGP and control. These results indicate that the dietary supplementation of DFM increases the growth performance of birds at an early age, stimulates the immune response, decreases the number of E. coli, and improves the ileal morphology of broiler chickens. Thus, DFM that contained a mixture of several beneficial microorganisms could be a viable alternative to antibiotics in the broiler diets.

Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Anti-Bacterial Agents; Cecum; Chickens; Diet; Dietary Supplements; Ileum; Male; Probiotics; Virginiamycin; Weight Gain

Shuttle programs involving dietary supplementation of mannanoligosaccharides (MOS) and virginiamycin (VM) were evaluated in turkeys by their effects on growth performance, body weight uniformity, and carcass yield characteristics. Diets containing no growth promoter (control), VM (22 mg/kg), or a shuttle program (MOS-VM) of MOS (0 to 6 wk of age at 500 mg/ kg) and VM (6 to 14 wk of age at 22 mg/kg) were fed to Hybrid female turkeys. All diets were formulated to exceed NRC nutrient requirements. Each treatment was assigned to 8 replicate floor pens containing 20 birds that were reared from 1 to 98 d of age. Body weights and feed consumption were recorded at 3-wk intervals, and mortality and culled birds were recorded daily. At the conclusion of the trial, 2 birds per pen were randomly chosen for carcass yield analysis. Feeding VM alone significantly (P < 0.05) increased body weight compared with control fed birds during all periods. The MOS-VM shuttle program resulted in early growth depression for birds less than 3 wk of age, possibly influenced by an unplanned cold stress, but better growth than the nonmedicated control birds after 6 wk of age. Birds fed VM had superior (P < 0.05) feed conversion ratio from 0 to 3 wk, which persisted until 14 wk (P < 0.10). There were no treatment effects on overall feed consumption, uniformity, mortality, or cull rate. Processing yields or weight of various parts were also unaffected by treatment.

Topics: Aging; Animal Feed; Animals; Anti-Bacterial Agents; Diet; Dietary Supplements; Drug Administration Schedule; Female; Mannans; Turkeys; Virginiamycin; Weight Gain

Virginiamycin (VM), a compound with proven performance-promoting properties in pigs, can also be considered as sow performance enhancer. The present dose titration study investigates the long-term effects of VM on gilt/sow and litter performance. A total of 140 healthy gilts, in 35 sets of 2 + 2 siblings each, were used in this trial; gilts in each set were randomly allocated to the four treatments (35 gilts per each treatment group): VM0 = negative control, virginiamycin 0 mg/kg, VM20 = virginiamycin 20 mg/kg, VM40 = virginiamycin 40 mg/kg and VM60 = virginiamycin 60 mg/kg of feed. VM was added to the gilt/sow feed for a period starting from 6 months of age up to conception of the fourth parity, covering three complete breeding cycles (pregnancy, lactation and weaning-to-conception interval). The feed given did not contain any other antibacterial agent or performance enhancer. Piglets were given exactly the same quantity of creep feed from the fifth day onwards; it did not contain any antibacterial agent or performance enhancer. The lactation period was the same in all gilts/sows (21 days). Results indicate that VM supplementation of the feed improved gilt/sow performance by: (i) increasing (P < 0.05) the mean body weight at each farrowing, (ii) decreasing (P < 0.05) the mean weight loss from farrowing to weaning, and (iii) decreasing (P < 0.05) the mean weaning-to-conception intervals. VM supplementation of gilt/sow feed also resulted in improved litter size and litter performance in terms of: (i) a higher (P < 0.05) mean number of piglets born alive at each birth, (ii) a higher (P < 0.05) mean number of piglets weaned, (iii) a higher (P < 0.05) mean piglet body weight at each birth, and (iv) a higher (P < 0.05) mean piglet body weight at each weaning. These beneficial effects of VM were more pronounced in the VM40 group.

Topics: Animals; Anti-Bacterial Agents; Dose-Response Relationship, Drug; Estrus; Female; Lactation; Male; Pregnancy; Pregnancy, Animal; Swine; Virginiamycin; Weight Gain

The aim of this study was to describe energy partitioning in dairy crossbreed bulls fed tropical forage-based diets supplemented with different additives. Twenty F1 crossbred bulls (Holstein x Gyr) with initial and final live weight (LW) averages of 190 ± 17 and 275 ± 20 kg were fed sorghum (Sorghum bicolour) and Tanzania grass (Panicum maximum cv. Tanzania) silage (70:30 DM basis) with supplemented concentrate at a forage to concentrate ratio of 50:50. The bulls were allocated to four treatment: control groups (without additives), monensin [22 mg/kg monensin dry matter (DM)] (M), virginiamycin (30 mg/kg virginiamycin DM) (V), and combination (22 mg/kg DM of monensin and 30 mg/kg DM of virginiamycin) (MV), in a completely randomised design. The intake of gross energy (GE, MJ/d), digestible energy (DE, MJ/d), metabolizable energy (ME, MJ/d), as well as energy losses in the form of faeces, urine, methane, heat production (HE), and retained energy (RE) were measured. Faecal output was measured in apparent digestibility trial. Right after the apparent digestibility trial, urine samples were collected in order to estimate the daily urinary production of the animals. Heat and methane production were measured in an open circuit respirometry chamber. The intake of GE, DE, and ME of the animals receiving monensin and virginiamycin alone or in combination (MV) showed no differences (P>0.05) from the control treatment. However, the MV treatment reduced (P<0.05) the methane production (5.44 MJ/d) compared to the control group (7.33 MJ/d), expressed in MJ per day, but not when expressed related to gross energy intake (GEI) (CH4, % GEI) (P = 0.34). Virginiamycin and monensin alone or in combination did not change (P>0.05) the utilization efficiency of ME for weight gain, RE and net gain energy. This study showed that for cattle fed tropical forages, the combination of virginiamycin and monensin as feed additives affected their energy metabolism by a reduction in the energy lost as methane.

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Cattle; Diet; Energy Intake; Energy Metabolism; Male; Monensin; Panicum; Sorghum; Virginiamycin; Weight Gain

This study aimed to evaluate the effect of virginiamycin on the metabolism and performance of growing Nellore bulls under low and high gain rates on pasture. In experiment 1, 80 Nellore bulls (age = 12 ± 2 months, body weight = 258 ± 15 kg) were assigned to 16 paddocks in a 2 × 2 randomized block factorial arrangement. In experiment 2, 12 cannulated Nellore bulls were assigned to three 4 × 4 balanced Latin squares. The factors were: (1) mineral salt without or with virginiamycin, and (2) low or high gain rate. No interaction was noted between factors (p > .10). Animals fed virginiamycin had greater average daily gain (14%, p < .01), body weight (11 kg, p = .05), plasma nonesterified fatty acid (20%, p < .01), serum calcium concentration (2.62%, p = .04), and total protozoa (p = .03) and had the same bacterial proportion (p > .27). Animals with a low gain rate had greater serum urea concentration (19.6%, p < .01) and ruminal ammonia nitrogen (62%, p < .01). Thus, virginiamycin increases the performance and changes the metabolism of growing Nellore bulls under low and high gain rates on pasture.

Topics: Ammonia; Animal Nutritional Physiological Phenomena; Animals; Calcium; Cattle; Diet; Dietary Supplements; Fatty Acids, Nonesterified; Herbivory; Male; Rumen; Urea; Virginiamycin; Weight Gain

This study evaluated the effect of increasing levels of monensin sodium (MON) in diets with virginiamycin (VM) on the finishing of feedlot cattle. Two hundred and eighty intact male Nellore cattle (348 ± 32 kg body weight, 22 months) received one of the following five diets: control diet (without additives); diet containing VM (25 mg per kg dry matter) combined with 0 (MON0), 10 (MON10), 20 (MON20) or 30 (MON30) mg MON per kg dry matter. During adaptation (28 days), the MON0 diet increased dietary net energy for maintenance and gain compared to the control diet (P = 0.04). The combination of additives linearly reduced dry matter intake, body weight and average daily gain (P < 0.01). Considering the total study period (110 days), there was a trend of greater net energy intake for maintenance (P = 0.09) and hot carcass weight (P = 0.06) for animals fed MON0 compared to the control diet. The combination of additives linearly reduced dry matter intake (P = 0.04) and linearly increased gain : feed and dietary net energy for maintenance and gain (P < 0.01). The combination of VM with MON at a dose of 30 mg/kg dry matter is recommended for Nellore feedlot cattle because it improves the efficiency of energy utilization.

Topics: Animals; Body Weight; Cattle; Diet; Dose-Response Relationship, Drug; Eating; Energy Intake; Energy Metabolism; Male; Monensin; Virginiamycin; Weight Gain

This study was performed to investigate the effect of dietary supplementation with Aloe vera (AV) powder and synbiotic as growth promoter agents on performance, gut morphology, immune responses, hematology and serum biochemistry in broilers. A total of 240-day-old male broiler chicks (Ross 308) were randomly assigned to six treatments with four replicates. Birds were offered either a corn-soybean meal basal diet (control) or the basal diet supplemented with 200 mg/kg virginiamycin (VM), 1 g/kg synbiotic (Syn), 2.5 g/kg AV (AV1), 5.0 g/kg AV (AV2) or 7.5 g/kg AV (AV3). Chickens fed any of the diets, except diet AV1, exhibited better feed conversion ratios at the 14-28 day period and higher average daily gain and duodenal villus height/crypt depth ratio at 42 days than those fed the control diet. Synbiotic supplementation caused a marked increase in the serum antibody titer against infectious bursal disease and infectious bronchitis vaccines. Feeding diet AV3 significantly increased red blood cell count and hemoglobin concentration, and decreased serum triglyceride level compared to the control group. The results suggested that dietary inclusion of 5 and 7.5 g/kg AV, similar with synbiotic supplementation, can be applied as effective alternatives to in-feed antibiotics for broiler diets.

Topics: Aloe; Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Antibodies; Chickens; Diet; Dietary Supplements; Duodenum; Erythrocyte Count; Glycine max; Hemoglobins; Male; Powders; Synbiotics; Triglycerides; Virginiamycin; Weight Gain; Zea mays

Two trials were conducted to evaluate the influence of virginiamycin supplementation on growth performance and digestive function. In trial 1, 144 Holstein steer calves (119 kg of initial BW) were used in a 340-d trial. Treatments were (DM basis) 1) control (no antibiotic); 2) 16 mg/kg of virginiamycin; 3) 22.5 mg/kg of virginiamycin; and 4) 28 mg/kg of monensin. Calves received a steam-flaked corn-based growing diet for the first 112 d and thereafter were fed a finishing diet from d 112 until slaughter. Steers were divided into 2 BW groups (lighter-half and heavier-half), and assigned within groups to 24 pens (6 steers/pen). Virginiamycin did not affect (P > 0.20) ADG, but increased 340-d G:F (linear; P = 0.02) and dietary NE (linear; P = 0.04). Improvements in dietary NE were most pronounced during the final 116 d of the feeding period (linear; P = 0.04) that comprised the hot summer months (June through September). Monensin did not affect (P > 0.20) growth performance or dietary NE. Although average initial BW of the lighter-half and heavier-half BW groups differed by only 4 kg, the heavier BW group had greater HCW (13 kg, P = 0.02), LM area (5.4%, P = 0.01), ADG (4.3%, P = 0.02), G:F (2.3%, P = 0.08), and dietary NE (3.2%. P = 0.01) than the lighter BW group. In trial 2, 4 Holstein steers (269 +/- 3.5 kg) with cannulas in the rumen and proximal duodenum were used in a 4 x 4 Latin square design to evaluate treatment effects on digestion. Virginiamycin did not affect (P > 0.20) ruminal digestion of OM, NDF, starch, and N, and microbial efficiency, but tended to linearly increase (P = 0.09) ruminal N efficiency (nonammonia N flow to the small intestine/N intake). Likewise, virginiamycin did not affect (P > 0.20) postruminal or total tract digestion of OM, starch, NDF, and N. Compared with the control diet, monensin depressed total tract digestion of OM (4.2%, P = 0.03) and NDF (29.5%, P = 0.02). There were no treatment effects (P > 0.20) on ruminal pH, or ruminal lactate and total VFA molar concentration. Virginiamycin increased ruminal molar proportion of acetate (quadratic; P = 0.04) and estimated methane production (quadratic; P = 0.07), and decreased propionate molar proportion (quadratic; P = 0.09). Monensin did not affect (P > 0.20) ruminal VFA molar proportions or estimated methane production. We concluded that virginiamycin supplementation can enhance feedlot growth-performance and dietary energetic efficiency of calf-fed Holstein steers.

Topics: Animals; Anti-Bacterial Agents; Cattle; Diet; Digestion; Duodenum; Energy Metabolism; Food Additives; Male; Monensin; Rumen; Virginiamycin; Weight Gain

(1) This in vivo trial was conducted to study the effects of polysaccharide extracts of two mushrooms, Lentinus edodes (LenE) and Tremella fuciformis (TreE), and a herb, Astragalus membranaceus (AstE) on growth performance, and the weights of organs and the gastrointestinal tract (GIT) of broiler chickens. (2) Three extracts (LenE, TreE and AstE) were supplemented at inclusion rates of 0.5, 1, 2, 3 and 4 g/kg from 7 to 14 d of age and compared with an antibiotic treatment group (20 mg/kg, virginiamycin (VRG) as well as a group of non-supplemented birds. (3) Body weight (BW) gain, feed intake and feed conversion ratio (FCR) of the extract-supplemented groups were not significantly different from those of the antibiotic group. Significant effects of type of extract and concentration on growth performance were found from 7 to 28 d of age. Generally, birds fed with LenE showed higher BW gain and lower FCR from 7 to 28 d of age than those fed with TreE and AstE and 2 g/kg LenE was considered the optimal inclusion rate for enhanced broiler growth. However, the extracts had no significant effect on the relative weights of organs and GIT compared with the antibiotic group. (4) The birds fed the extracts showed better growth performance than the non-supplemented birds, but were not significantly different from those fed VRG. Of the three extracts, LenE appeared to be a potential growth promoter. Future studies are needed to investigate whether the extracts can be used as alternatives for antibiotic growth promoters in challenged birds, and to elucidate the mechanisms for potentially enhanced growth performance in poultry.

Topics: Animal Nutritional Physiological Phenomena; Animals; Anti-Bacterial Agents; Astragalus propinquus; Basidiomycota; Chickens; Diet; Dietary Supplements; Gastrointestinal Tract; Organ Size; Polysaccharides; Shiitake Mushrooms; Virginiamycin; Weight Gain

A study was conducted to evaluate the effects of mannanoligosaccharides (MOS), bambermycins (BAM), and virginiamycin (VIR) on the growth performance of male turkeys. Hybrid Large White male poults were assigned to six dietary treatments: control, MOS, BAM, VIR, MOS+BAM (MB), and MOS+VIR (MV). All diets were formulated to meet NRC (1994) nutrient requirements. There were eight replicate floor pens per treatment with 20 birds per pen reared from 1 to 140 d. Body weight and feed conversion (FC) were collected at 3-wk intervals and at 20 wk of age. Mortality and culled birds were recorded daily. All treatments except MV significantly (P < 0.05) increased 20 wk BW. Body weight was increased at 12 wk by BAM, whereas VIR increased BW at Weeks 12 and 15. All treatments improved FC for Weeks 0 to 3, whereas VIR, MB, and MV improved FC for Weeks 0 to 12 and 0 to 18. There were no treatment effects on cumulative mortality or cull rate. Dietary supplemental MOS, BAM, and VIR resulted in improved growth performance of Large White turkeys. These results indicate that MOS may be utilized as an alternative to antibiotic growth promotants to improve turkey performance.

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Bambermycins; Body Weight; Dietary Supplements; Energy Metabolism; Male; Mannose; Oligosaccharides; Random Allocation; Turkeys; Virginiamycin; Weight Gain

Two experiments were conducted to determine the effect of sucrose thermal oligosaccharide caramel (STOC) and dietary vitamin-mineral (V/M) level on growth performance and intestinal microflora of broiler chickens. In Experiment 1, Peterson x Arbor Acres male broilers (n = 384) were randomly allocated into four groups that were fed either the control diet or diets containing the antibiotic virginiamycin (11 mg/kg), 3.7% STOC or 7.5% STOC for 4 wk at brooding temperatures of 32 to 29.7 C. Weight gains for broilers in Experiment 1 were greater (P < 0.001) for birds fed STOC diets, with weight gains of 763, 822, 1,124, and 1,080 g for birds on the control, antibiotic, 3.7% STOC, and 7.5% STOC diets, respectively. Feed intake and feed conversion by birds fed STOC diets were also significantly improved. Cecal bifidobacterial numbers were increased (P < 0.03) over the control diet with numbers being 5.98, 6.99, 7.47, and 7.39 log10 cfu/g cecal DM, respectively. In Experiment 2, Peterson x Hubbard male broilers (n = 384) were used in a 2 x 2 x 2 factorial arrangement with two levels of V/M premix (0.5 or 1% of the diet), two levels of STOC (0 or 3.5% of the diet), and two brooding temperatures, normal (32 to 23.6 C) or high (32 to 29.7 C) for 4 wk. Feeding the STOC diet improved (P < 0.05) weight gain, feed intake, and feed conversion of broilers. The effect of STOC on animal performance was less evident when broilers were fed twice the NRC recommended levels of V/M. Feeding the STOC diets resulted in a significantly greater increase in weight gain at high brooding temperatures than at normal brooding temperatures. There was also a reduction (P < 0.05) in numbers of total aerobes and coliforms in the ceca of birds fed diets containing STOC. Feeding STOC has potential to improve growth performance of broiler chickens.

Topics: Actinomycetales Infections; Animals; Anti-Bacterial Agents; Bifidobacterium; Chickens; Diet; Dietary Carbohydrates; Dietary Sucrose; Dose-Response Relationship, Drug; Eating; Food, Fortified; Intestines; Male; Minerals; Oligosaccharides; Poultry Diseases; Random Allocation; Temperature; Virginiamycin; Vitamins; Weight Gain

One experiment utilizing Cobb x Cobb male broilers was conducted to evaluate virginiamycin (VM; 0, 15, 20 ppm) and diet caloric density (CD; 2,945, 3,200 AMEn/kg) effects on broiler live performance, blood serum metabolites, and carcass composition. The starter period exposed birds to recommended brooding conditions, whereas from 3 to 7 wk birds were exposed to thermoneutral (TN, 24 C) or cycling temperature (CT, 24 to 35 C) environments (E). During the 21-d starter period, VM levels and high CD increased (P < 0.05) BW gain (G) and gain:feed (G:F) improved (P < 0.05) with 20 ppm VM and high CD. During 3 to 7 wk, CT reduced (P < 0.05) most live performance and carcass variables as well as heat production (HP) and energetic efficiency whereas energy content per gram of tissue increased. The main effect of VM and CD on blood serum constituents was not significant; however, CT decreased (P < 0.05) serum Na, K, Ca, Mg, Fe, albumin, and total protein. Within CT, G increased (P < 0.05) with high CD and with the 15 ppm VM combination, whereas within TN, G was unaffected by CD, but increased (P < 0.05) with the 20 ppm VM and low CD combination compared with the control. High CD increased (P < 0.05) BW, G, carcass weight, dressing percentage, carcass percentage fat, carcass dry matter, carcass energy content per bird, HP, fat, and protein gain but reduced (P < 0.05) carcass percentage protein and energetic efficiency. Carcass weight, breast yield, fat, and protein gains as well as dry matter carcass energy content increased (P < 0.05) with VM compared with controls. The reduced (P < 0.05) calorie intake and HP with concomitant increase (P < 0.05) in calorie gain with 20 ppm VM increased (P < 0.05) caloric efficiency. In summary, the results suggest that VM improves bird performance by reducing HP and that reduced HP during high CT improves body temperature homeostasis.

Topics: Animals; Anti-Bacterial Agents; Body Composition; Body Temperature Regulation; Calcium; Chickens; Diet; Eating; Energy Intake; Hot Temperature; Immunoglobulin G; Immunoglobulin M; Iron; Magnesium; Male; Potassium; Random Allocation; Serum Albumin; Sodium; Specific Gravity; Temperature; Virginiamycin; Weight Gain

The effects of dietary virginiamycin level on performance and liver abscesses in feedlot cattle were evaluated in seven dose-response studies. Steers and heifers were fed finishing diets ranging in energy content from 1.34 to 1.51 Mcal of NEg/kg of DM. In all studies, virginiamycin added to the diet improved average daily gain and(or) feed conversion, with no substantial effect on dry matter intake. Pooled analyses of four studies providing virginiamycin at 11.0, 19.3, and 27.6 mg/kg of DM in the complete diet indicated that growth and feed conversion were linearly improved (P < .05); feeding 19.3 mg/kg improved these measurements by 3.0 and 3.8%, respectively. Overall incidence (score 0 vs score 1, 2, and 3) and severity (score 0, 1, and 2 vs score 3) of liver abscesses were reduced (P < .01) by feeding virginiamycin at either 19.3 or 27.6 mg/kg. Linear plateau modeling indicated that the effective dose range for virginiamycin in feedlot diets (DM basis) was 19.3 to 27.3 mg/kg for increasing average daily gain, 13.2 to 19.3 mg/kg for improving feed conversion, and 16.5 to 19.3 mg/kg for reducing liver abscess incidence.

Topics: Animals; Cattle; Cattle Diseases; Diet; Dose-Response Relationship, Drug; Eating; Female; Incidence; Linear Models; Liver Abscess; Male; Random Allocation; Severity of Illness Index; Virginiamycin; Weight Gain

1. An experiment was carried out with male broiler chicks to evaluate the combined effect of monensin (150 mg/kg) and the growth promoters (GPs) Zn bacitracin (BAC, 50 mg/kg), virginiamycin (VIR, 25 mg/kg) and avoparcin (AVO, 20 mg/kg) fed from 7 to 28 d of age on performance, utilisation of dietary nutrients, yield of defeathered eviscerated carcases (DEC) and size of various organs. The effect of the GPs in the monensin-unsupplemented diets fed up to 49 d of age on performance and carcase was also determined. 2. Monensin significantly (P < 0.05) depressed food intake, weight gain and food efficiency from 7 to 28 d of age. None of the GPs was able to counteract these effects. However, AVO slightly ameliorated them. AVO also significantly increased food intake and improved gain and food efficiency during 7 to 28, but not 28 to 49 or 7 to 49 d of age. VIR and BAC did not affect performance in either age period. 3. Monensin did not affect the utilisation of dietary dry matter, fat or energy, but it significantly decreased nitrogen utilisation. AVO improved nitrogen and fat utilisation and increased dietary AME(n) content. AME(n) was also increased by VIR. The utilisation of these nutrients was not affected by the interactions between monensin and the GPs. 4. Monensin did not affect yield of the DEC or the relative liver size at 31 d of age. It significantly increased the relative length of the small intestine (SI) and decreased its specific weight. AVO significantly increased yield at 31, but not at 53 d of age. BAC and VIR did not affect this variable. AVO and VIR, but not BAC, at both age periods reduced, at times significantly, the size, length and specific weight of the SI. 5. Our conclusions: BAC, VIR and AVO do not counteract the toxic effect of monensin. The effect of GPs in improving performance decreases and even disappears with age, while their effect in reducing the size of the SI is still evident in 49-d-old birds.

Topics: Animal Nutritional Physiological Phenomena; Animals; Anti-Bacterial Agents; Bacitracin; Chickens; Drug Interactions; Eating; Glycopeptides; Male; Monensin; Virginiamycin; Weight Gain

The effect of a peptolide antibiotic virginiamycin on the growth, rumen and blood parameters was followed in 8 milk-fed calves, 4 weeks old initially. Calves were individually housed in metabolic cages. The experiment was ended at the age of 16 weeks. Virginiamycin was supplied at 80 mg per head per day. Calves receiving virginiamycin gained 5.1% more than control calves. Feed intake per 1 kg of body weight gain was higher in control calves. Virginiamycin significantly increased molar percentage of propionate and decreased molar acetate: propionate ratio in rumen fluid. Serum iron, hematocrit and hemoglobin were significantly increased in the treated group in the last period of the trial. Virginiamycin lowered serum protein and urea and tended to decrease activity of aminotransferases.

Topics: Animals; Cattle; Digestion; Eating; Fatty Acids, Volatile; Hematocrit; Hemoglobins; Iron; Male; Rumen; Virginiamycin; Weight Gain

1. Two factorial experiments were carried out with male broiler chicks from 6 to 28 (experiment 1) and from 7 to 49 (experiment 2) d of age to evaluate the combined effect of virginiamycin (VIR), dietary energy concentration, and energy-to-protein (E:P) ratio on performance and the utilisation of dietary nutrients. 2. VIR had no significant effect in either experiment on food intake or weight gain, but significantly improved food efficiency up to 28 d of age (P less than 0.001 and P less than 0.05 in experiments 1 and 2, respectively). 3. VIR consistently and significantly (P less than 0.01) decreased fat excretion, improved fat relative retention and increased dietary AMEn. VIR also significantly (P less than 0.01) increased relative retention of dry matter, while it did not affect nitrogen balance. 4. Neither of the variables of performance and utilisation of dietary nutrients was affected by the interactions between VIR and either dietary E:P ratio or energy concentration. It is concluded, therefore, that the effect of VIR in increasing the utilisation of dietary energy does not depend on the above factors.

Topics: Animal Feed; Animals; Chickens; Dietary Fats; Dietary Proteins; Eating; Energy Intake; Energy Metabolism; Male; Virginiamycin; Weight Gain

Efficacy of virginiamycin (22 mg/kg) in combination with no drug, amprolium, carbarsone, halofuginone, or monensin, was studied. Male and female turkeys were raised to market age in five experiments conducted from 1983 to 1987. Body weights and feed:gain responses to virginiamycin for males and females were positive and significant (P less than .05). Virginiamycin resulted in mean 5.2 and 6.3% body weight responses and 3.3 and 2.2% feed:gain responses for males at 19 or 20 wk of age and for females at 16 or 17 wk of age, respectively. Mortality rates were low in all studies, and were not influenced by virginiamycin. In a processing study, virginiamycin in combination with halofuginone did not affect shrinkage, yield, or market grade. Feed was utilized by males and females 3.9 and 3.0%, respectively, more efficiently than expected with dietary virginiamycin, compared with results predicted by a simulation modeling technique. Profitability was considerably greater with dietary virginiamycin using actual data than with simulated feed consumption data.

Topics: Amebicides; Amprolium; Animal Feed; Animals; Arsanilic Acid; Drug Interactions; Eating; Energy Metabolism; Female; Male; Monensin; Mortality; Piperidines; Quinazolines; Quinazolinones; Sex Characteristics; Turkeys; Virginiamycin; Weight Gain

Diets supplemented with either 22 mg of virginiamycin per kg, 99 mg monensin sodium per kg, or both, were fed to 960 Hybrid-1500 Medium White poults from day-old to slaughter at 12 wk of age. Weight gains from 0 to 12 wk were greater when the diet was supplemented with virginiamycin, alone or in combination with monensin (P less than .05). However, the combination of virginiamycin with monensin resulted in superior overall feed efficiency to that obtained with either additive alone.

Topics: Animals; Diet; Female; Male; Monensin; Random Allocation; Turkeys; Virginiamycin; Weight Gain

Diets containing 0 or 22 mg of virginiamycin per kilogram were fed to 448 Nicholas Large White turkeys from day-old to slaughter at 16 (females) or 20 wk of age (males). Weight gain of males, but not females, fed treated diets increased significantly from 0 to 4 and 4 to 8 wk of age, but not in later periods. However, final weights of both sexes were increased by treatment with virginiamycin. Feed efficiency of treated birds increased to 8 wk of age but not overall. Mortality and carcass finish and fleshing scores were unaffected by the antibiotic treatment.

Topics: Animals; Eating; Female; Male; Sex Factors; Time Factors; Turkeys; Virginiamycin; Weight Gain