An alternative to antibiotic-based drugs in feed for enhancing performance of broilers grown on Eimeria spp.-infected litter.

Three trials were conducted to evaluate the effects of lasalocid, an anticoccidial feed additive (90.7 kg/ton); bacitracin, a growth-promoter (50 g/ton); and yeast culture residue (YCR) (1 kg/ton) on the performance of broiler chicks reared to 42 d of age on recycled litter. Recycled litter consisted of pine wood shavings containing droppings from chicks infected with 3 select strains of coccidia (Eimeria tenella, Eimeria maxima, and Eimeria acervulina). Response variables (BW, intestinal tract and litter coliform counts, cecal and liver relative weights, and litter moisture content) were recorded biweekly. Mean BW of chicks fed the diet supplemented with YCR was higher than that of the controls (P < 0.05) and comparable to that of the lasalocid-treated birds in all 3 trials. Mean BW of chicks in all treatment groups decreased uniformly as the litter aged and moisture content increased. The mean intestinal coliform population from YCR-treated chicks was lower (P < 0.05) than those of the control and lasalocid populations. The coliform count was consistently lower than that in chicks on a bacitracin-supplemented diet. Coliform counts from the control and lasalocid-treated birds did not differ. The litter coliform counts increased with increased use of the litter. Cecal and liver relative weights calculated from the chicks in trial 3 showed that only the liver was significantly affected by treatments. YCR appeared to be a viable alternative to bacitracin and lasalocid medication in enhancing growth of broiler chicks reared on recycled litter.

Response of broiler chickens to dietary supplementation with roxarsone and bacitracin methylene disalicylate in diets containing narasin.

Six trials were conducted at different locations to examine the response of broiler chickens to roxarsone and bacitracin in the form of bacitracin methylene disalicylate (BMD) in the presence of the anticoccidal narasin. All diets contained narasin (80 mg/kg) and were fortified with a factorial arrangement of roxarsone (0 to 50 mg/kg) and BMD (0 or 55 mg/kg). Broilers were grown to market weights with narasin and roxarsone removed from the diets for the final 5 days. Addition of both roxarsone and BMD resulted in significant (P less than .05) improvements in body weight and feed utilization. Response to roxarsone for feed utilization was influenced to some extent by the presence or absence of BMD. Although the response to roxarsone was always positive, the degree of response was lessened by the presence of BMD. This resulted in a significant (P less than .10) interaction between roxarsone and BMD for feed utilization but not for body weight.

Relationship of biotin to reproductive performance of Leghorn-type hens.

Five floor pens with 14 Leghorn-type breeder hens each, in their 4th month of production, and 2 males per pen were fed a practical-type breeder diet composed largely of soybean meal and milo supplemented with unidentified hatchability factor sources and adequate levels of vitamins and minerals. Five additional pens were fed an identical ration supplemented with biotin at a level of 550 mcg./kg. of diet. Treatment was for a period of 7 months. A 3% improvement in production was obtained by biotin (550 mcg./kg.) supplementation, which was found to be highly significant (P less than or equal to .005) by chi-square analysis. A slight improvement was noted for feed efficiency. Biotin supplementation had no effect on egg size or adult livability. Fertility and hatchability were both significantly improved by biotin supplementation. Fertility and hatchability differences were found to be highly significant by chi-square analyses. Increased hatchability was due to a decreased number of early dead, late dead, and pipped embryos that failed to hatch.

Amino acid supplementation of low protein turkey starting rations.

Turkey poults fed rations containing 22.1% protein had a much slower rate of growth when compared with poults receiving a ration containing 29.8% protein. Methionine supplementation had no effect on body weight and mortality to 18 days of age. Supplementation of the 22.1% protein diet with lysine (0.2%) significantly improved growth rate over the unsupplemented 22.1% protein diet. The addition of methionine to the 22.1% protein diet supplemented with lysine (0.2%) produced slight additional response in body weight; however the drop in mortality was much more dramatic as increments of methionine were added to the 22.1% protein diet supplemented with lysine (0.2%).

Amino acid supplementation of turkey breeder rations.

Beltsville Small White turkey hens (60) were randomized into four groups of 15 hens each, weighed and placed in individual laying cages. Immediately after lighting to initiate production, they were placed on a practical type turkey breeder diet calculated to contain 18.26% protein, 2893 Cal. M.E./kg., 3.13% Ca, 0.80% available P, 1.04% arginine, 0.86% lysine, 0.50% methionine & cystine and 0.24% tryptophane. Amino acids were added to this diet as follows: (1) none; (2) 0.1% lysine; (3) 0.05% methionine and (4) 0.1% lysine & 0.05% methionine. Lysine (0.1%) had no effect on reproductive performance when added to the basal ration or to the ration containing additional methionine. Methionine addition (0.05%) improved production significantly (P less than or equal to .005), improved feed efficiency, and increased egg size.

Biotin and early poult growth.

Commerical Broad Breasted White male poults were fed either a soybean and milo ration, or similar rations containing 7.5% or 20% animal protein, for a period of 0-8 weeks. Three groups of 48 birds each were fed each of the three rations which were isocaloric (2926 M.E. Cal. /Kg. of ration) but differed slightly in protein content. Other groups were fed identical rations supplemented with biotin at a level of 220 mcg/kg. When the growth data were analyzed by analysis of variance, highly significant differences noted for treatment (P less than or equal to 0.01). Biotin supplementation of the soybean-milo ration gave no response, but supplementation of the rations containing animal protein with biotin gave excellent growth responses. When the data were combined so that the effect of biotin could be evaluated, a highly significant (P less than or equal to 0.005) improvement in growth was obtained by supplementing the rations with biotin. Feed efficiency was found to be closely related to growth rate. Mortality did not appear to be related to diet, with the differences being non-significant statistically.