Two experiments were conducted to determine the influence of Streptococcus faecium M-74 supplementation of broiler diets. Mixed-sex or male only chicks were used in the experiments. Both experiments consisted of six dietary treatments and four replicates per treatment in a randomized block design. The S. faecium was fed alone for 21, 36, or 44 days or for 44 days with S. faecium supplemented in the water for the first 14 days. In another treatment, S. faecium was fed for 44 days, but the feed was restricted for Days 8 through 13. The S. faecium was also fed in combination with antibacterial products (AP) for 44 days. An additional diet was an unsupplemented basal, and another was supplemented only with AP. In Experiment 1, feed efficiency was significantly better with the basal and diets supplemented with S. faecium than with those diets supplemented with AP or AP and S. faecium. In Experiment 2, BW of broilers at 44 days of age were significantly heavier for broilers receiving S. faecium in the feed and also S. faecium in the water for the first 14 days as compared with broilers receiving AP or AP and S. faecium supplementation. There were no significant differences in carcass yield or composition characteristics. In Experiment 1, the scores representing S. faecium colonies found in the intestinal tract were not influenced by dietary treatment. The ceca had the highest S. faecium score of any of the intestinal tract locations.(ABSTRACT TRUNCATED AT 250 WORDS)

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An experiment was conducted to obtain information on the concept of progressively decreasing dietary phosphorus levels (phase feeding) on the performance of three different commercial layer strains. Dietary available phosphorus (AP) levels of .15, .30, or .45% were fed continuously from 22 to 70 weeks of age. Concurrently, a diet containing .35, .25, and .15% AP was phase-fed during age intervals of 22 to 34, 34 to 50, and 50 to 70 weeks, respectively. Dietary AP levels did not significantly affect egg production except the .15% AP level, which significantly reduced egg production when compared with the other three dietary AP treatments. Efficiency of feed utilization was significantly superior for hens phase-fed AP compared with hens fed the other AP treatments. There were no differences in egg weight or mortality due to dietary AP. Eggshells were significantly thicker when hens received .15% AP. The .15% AP and phase-fed regimen resulted in hens with significantly lower body weights at the end of the experiment. Hens fed .30% AP and phase-fed AP had significantly lower carcass ash and phosphorus levels. Serum phosphorus levels corresponded directly to dietary AP levels. There were no significant differences in egg production due to strain nor were there any strain by dietary treatment interactions that influenced production traits. Significant strain differences were noted in feed efficiency, egg weight, carcass ash, and carcass phosphorus.

Two experiments were conducted with commercial strain, White Leghorn laying hens, kept in wire cages, to determine the effect of low dietary phosphorus (P) levels on production characteristics. In experiment 1, rations that contained 0.19, 0.28 or 0.37% available P (AP) were fed to 22 week old hens. The total (TP) and inorganic (IP) levels of these rations were 0.42, 0.51, 0.60% and 0.09, 0.18, 0.27%, respectively. All dietary P levels supported a high rate of egg production during the 140-day trial. Ration treatments did not affect feed consumption, feed efficiency or average egg weight. Mortality, however, was slightly higher for hens fed 0.19% AP. The second experiment utilized 47 week old hens of a different strain. A basal ration containing 0.10% AP (0.30% TP all from plant sources) was used as one ration treatment. Three additional treatments were obtained by including defluorinated rock phosphate in the diet to supply 0.09, 0.18 or 0.27% IP. Egg production by hens fed 0.10% AP decreased markedly within four weeks, while egg production by hens fed 0.19% or more AP (0.09% or more IP) continued at a high rate throughout the 56-day trial. Hens fed 0.10% AP also lost considerable body weight and suffered a relatively high death loss. Feed consumption and femur ash were not affected significantly by dietary P. The results indicated that relatively low dietary P levels can fulfill the laying hen's requirement for egg production provided that about 0.19% or more AP is present in the ration. To maintain livability, as well, the AP requirement may be at least 0.28%.

An experiment was conducted to determine the independent and interaction effects of dietary metabolizable energy (ME) and protein concentrations on performance of Large White toms from 9 to 20 weeks of age. Diet treatments consisted of a complete factorial arrangement of three ME concentrations and three protein concentrations within each age interval (9 to 12, 12 to 16, and 16 to 20 weeks). The different ME concentrations were obtained by using an animal-vegetable fat blend at 0, 4, or 8% of the diets. Dietary protein levels tested provided approximately 88, 97, or 107% of those recommended by National Research Council (1977) for each age interval. The ME concentrations represented 95, 100, or 105% of those used most frequently in commercial feeding programs in the central United States. Dietary ME and protein concentrations had significant (P less than .03) independent effects on turkey performance. As each diet variable was increased, gain in body weight and feed efficiency were improved. Increasing dietary ME reduced the amount of protein consumed per kilogram of gain but not the ME consumed per kilogram of gain. Protein consumed per kilogram gain increased as dietary protein increased, while ME intake per kilogram gain decreased. Carcass composition and parts yield of the carcass were affected only slightly by dietary ME and protein concentration. No significant (P greater than .10) interaction effects of dietary ME and protein were detected, except in the instance of absolute quantity of carcass protein (P less than .07).(ABSTRACT TRUNCATED AT 250 WORDS)