Standardized ileal digestible lysine requirements for 7- to 11-kg weanling pigs fed a corn-soybean meal-based diet

Amino acid requirements are known to vary with pig genotype and using the cost estimates has economic as well as environmental implications. The objective of this research was to determine the standardized ileal digestible (SID) lysine (Lys) requirements for 7- to 11-kg weanling pigs (TN Tempo × TN70) fed a corn-soybean meal-based diet. A total of 144 piglets (6.51 ± 0.56 kg BW) were assigned to 1 of 6 diets using a randomized complete block design based on body weight to give 8 replicate pens with 3 pigs per pen. The six diets contained 1.00, 1.16, 1.32, 1.48, 1.64, and 1.80% SID Lys, respectively. Piglets had free access to diets and water for 14 days. Average daily gain (ADG) and average daily feed intake were not affected by dietary SID Lys content during the first 7 days, however, the addition of dietary SID Lys quadratically increased (P < 0.05) gain:feed (G:F) of piglets. A quadratic increase (P < 0.05) was found in ADG when SID Lys content increased in the diets from day 7 to 14. During the overall experimental period, increasing dietary Lys content quadratically increased (P < 0.05) ADG and G:F, whereas plasma urea nitrogen was quadratically decreased (P < 0.05) as SID Lys content increased. The SID Lys requirements for optimal growth performance of 7- to 11-kg weanling pigs fed corn-soybean meal-based diets ranged from 1.28 to 1.44% for ADG and 1.38 to 1.55% for G:F, respectively, thus giving an overall average value of 1.42%. These results contribute to understand more accurate Lys requirements in weaning pigs, which is required for optimal formulation of the swine diets. The determined Lys requirement value can be used to formulate diets that closely meet amino acid requirement for high lean pig genotypes. This has the added advantage of minimizing nitrogen excretion into the environment and saving the feed cost. 

Key words: broken-line analysis, growth performance, lysine, piglets.

Published in the proceedings of the Animal Nutrition Conference of Canada 2020. For information on the event, past and future editions, check out https://animalnutritionconference.ca/.