Effects of increased dietary lysine (protein) Level on performance and carcass characteristics of growing-finishing pigs reared in a hot, Humid environment

摘要

A study was conducted to evaluate the effects of rearing environment/season (hot, humid/summer vs thermoneutral/fall) and dietary lysine level (at or above current NRC recommendations) on performance and carcass lean content of growing-finishingpigs. Two trials, each involving 90 crossbred pigs, were conducted-one during the summer and the other during the fall-early winter The trials were conducted in Northwest Florida (31°N). Average daily low and high temperatures, and average relativehumidities, respectively, were: 21℃, 32℃, and 81 for summer; and 8℃, 21℃, and 84 for fall. Ten pigs (five males, five females) were allotted to a pen and each pen was assigned to one of three dietary lysine level treatments (0.75 grower/0. 6finisher 0.85/0. 7 or 0.95/0.8) within each of three replicates. Corn-soybean meal-based grower diets were fed from 29 to 58 kg average body weight and finisher diets from 58 to 112 kg. The desired dietary lysine levels were obtained by altering thelevels of corn and soybean meal. Pigs were housed in a curtain-sided building in pens with solid concrete floors that had an open water waste flush gutter across the rear 20 of the pen. Floor space per pig was 0.72 m{sup}2. Over the entiregrowing-finishing phases, pigs reared during the summer grew 11 slower (P 0.10) by dietary lysine (protein) content for pigs reared in either environment. A hot, humid summer rearing environment had an adverse effect on growing-finishing pig performance and increasing the dietary lysine had noeffect.