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Two trials were conducted to determine the amino acid and protein requirements of broiler breeders at peak production. In trial 1, 32-wk-old Cobb 500 broiler breeders with similar BW were selected to determine the digestible amino acid requirement for daily product output (g of egg mass + g of BW gain/b/d) and feed conversion (g of feed/g of product) for Met, Phe, Arg, Ile, Lys, and CP in a 42-d production study. In trial 2, 30-wk-old Cobb 500 broiler breeders were selected to determine the digestible requirement for Met, Lys, Ile, Arg, Cys, Val, Trp, and Thr in a 70-d production study. Breeders were given a corn-soy basal diet plus crystalline amino acids with 8 graded levels of amino acids (10 birds per level), representing 40 to 130% of the highest suggested requirements reported in the literature. All other amino acids were maintained at 100% of their suggested requirement level. All breeders were inseminated weekly and fertility was determined. A third trial consisted of 41-wk-old colostomized hens randomly assigned to 1 of 2 diets differing only in the amount of Ile. Urine was collected after a 6-wk feeding period. The average digestible requirements per breeder per day for both product and feed/product ratio from trials 1 and 2 for Met, Cys, TSAA, Phe, Phe + Tyr, Trp, Arg, Ile, Lys, Val, Thr, and CP were 424, 477, 901, 689, 997, 252, 1,026, 830, 916, 799, 613 mg/d, and 20.0 g/d, respectively. The ideal profile for digestible Met, Cys, TSAA, Phe, Phe + Tyr, Trp, Arg, Ile, Lys, Val, and Thr was 46, 52, 98, 76, 108, 28, 112.0, 91, 100.0, 87, and 67%, respectively. A significant decrease in fertility was noted with increasing levels of Ile and Lys. Urine pH was significantly more alkaline in hens fed the higher level of Ile. It is suggested that adequate dietary Lys and Ile should be provided for maximum hatching egg production but an excess may affect fertility.

SummaryThe impact of crossing (‘stacking’) genetically modified (GM) events on maize‐grain biochemical composition was compared with the impact of generating nonGM hybrids. The compositional similarity of seven GM stacks containing event DAS‐Ø15Ø7‐1, and their matched nonGM near‐isogenic hybrids (iso‐hybrids) was compared with the compositional similarity of concurrently grown nonGM hybrids and these same iso‐hybrids. Scatter plots were used to visualize comparisons among hybrids and a coefficient of identity (per cent of variation explained by line of identity) was calculated to quantify the relationships within analyte profiles. The composition of GM breeding stacks was more similar to the composition of iso‐hybrids than was the composition of nonGM hybrids. NonGM breeding more strongly influenced crop composition than did transgenesis or stacking of GM events. These findings call into question the value of uniquely requiring composition studies for GM crops, especially for breeding stacks composed of GM events previously found to be compositionally normal.

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Two experiments were conducted to determine the nutritional and metabolic impacts of defatted green microalgal (Desmodesmus sp.) biomass (DGM), protease, and nonstarch polysaccharide degrading enzymes (NSPase) in diets for weanling pigs and broiler chicks. Pigs fed 10% DGM for 28 days had growth performance comparable to the controls, but 23-39% lower (P < 0.05) plasma urea nitrogen concentrations. Broilers fed 15% DGM had 16% greater (P < 0.05) gain/feed efficiency than the control (0.78 vs 0.67) over the 42 day period. Supplemental protease (0.06%) decreased (P < 0.03) plasma uric acid concentrations in pigs on day 14, whereas supplemental NSPase showed negative effects in broilers. Dietary inclusions of DGM or enzymes altered (P < 0.05-0.1) hepatic and muscle protein levels of key regulators in the mTOR pathway. In conclusion, weanling pigs and broiler chicks tolerated dietary inclusions of 10 and 15% DGM, respectively, and adding protease might help digestion.