Interactive effects of thermal environment and dietary lysine and fat levels on rate, efficiency, and composition of growth of weanling pigs.
Two trials involving 96 weanling pigs were conducted in which pigs were maintained in constant thermal environments of 20 degrees (cool) or 32 degrees C (hot) and self-fed fortified corn-soybean meal-whey diets that contained three amino acid regimens (.7, 1.0, or 1.3% lysine; approximately 13.6, 17.8, and 22.0% CP) without and with 5% added fat (choice white grease) for 42 d. The pigs were weaned between 28 and 32 d of age (8.07 +/- .58 kg) and penned in groups of two. Pigs in the cool environment consumed more (P < .01) feed and ME, gained more (P < .01) weight, and retained more (P < .01) body protein, fat, and water than those housed in the hot environment. As dietary lysine level increased, daily BW gain and body protein and water accretion increased linearly (P < .01) from d 0 to 21 and quadratically (P < .01) from d 21 to 42 in both environments. However, the magnitude of these responses was less (P < .05) in the cool than in the hot environment. Dietary fat addition decreased (P < .05) gain:ME ratios and body protein and water accretion from d 0 to 21 in both environments, but the magnitude of the reduction was greatest in pigs fed the low lysine diets in the hot environment. Based on these data, the growth response of weanling pigs to dietary lysine and fat levels is dependent on the thermal environment in which the animals are housed.
Schenck
B C
BC
Department of Animal Sciences, University of Kentucky, Lexington 40546.
Stahly
T S
TS
Cromwell
G L
GL
D000596:Amino Acids / Q000008:administration & dosage; D000821:Animal Feed; D000818:Animals; D001823:Body Composition; D004041:Dietary Fats / Q000008:administration & dosage*; D004435:Eating; D002149:Energy Intake; D008239:Lysine / Q000008:administration & dosage*; D011897:Random Allocation; D013552:Swine / Q000254:growth & development*; D013696:Temperature; D013997:Time Factors; D015430:Weight Gain
D000596:Amino Acids; D004041:Dietary Fats; D008239:Lysine