Choline has been demonstrated to partially substitute methionine in broiler chicken diets due to their interconnected biosynthesis pathways. Yet, research on the impacts of dietary choline supplementation on modern strains of high-yielding broilers is limited. The objective was to evaluate the effect of increasing additions of choline chloride on the performance and carcass characteristics of broilers fed reduced methionine diets and reared under summer environmental conditions. Ross 708 x Yield Plus male broilers were reared for 41 days on used litter in floor pens (n = 2232; 31 birds per pen). Birds were fed one of six corn and soybean meal-based, reduced methionine diets containing 0, 400, 800, 1200, 1600, or 2000 mg of added choline chloride per kg of feed. Diets were provided in three phases. On day 43, 10 birds per pen were processed. Increasing dietary choline resulted in similar body weight gain, reduced feed intake, and improved feed efficiency. Choline chloride supplementation linearly increased both breast and carcass yields while concomitantly increasing the incidence and severity of wooden-breast-affected fillets. These results indicate that supplementing reduced-methionine broiler diets with choline chloride during high environmental temperatures may improve feed efficiency and increase carcass and breast yields but may also increase wooden breast.

While productivity increases in the production of aquaculture have contributed to reductions in greenhouse gas emissions per unit of production, additional reductions in green-house gas emissions can be attained by modifying the ingredients in the selected studied species, i.e., Nile tilapia, salmon and shrimp diets. In this paper, a baseline diet, for a given studied species, was aggregated from at least four commercial diets to have a better representation of the real world. Then using the same list of feed ingredients, an alternative scenario was defined not only balancing the ration from energy, protein and fat nutrient requirements, and constraining the cap at 150% for individual feed ingredient from the baseline diet but also minimizing the greenhouse gas emission. For all three studied species, 8.4% less plant-based protein meals, 23.9% less grains, and 36.8% more animal protein meals were used in the scenario diet. In consequence, total greenhouse gas emissions was reduced by 15.3% from the baseline diet and total acres of land use was decreased by 20%.