The effects of dietary protein digestion kinetics and protein levels in lactating sow diets on reproductive performances and litter characteristics

During lactation, sows need to mobilize their body reserves to support milk production, as the voluntary feed intake does not cover their nutritional demands during this period. An increased litter size in the last decades has increased sows’ lactational burden, which increases concerns about the higher body condition losses in modern sows during lactation. As sow body fat reserves have decreased in modern lean genotypes, the body condition loss during lactation increasingly consists of protein tissue.

Higher maternal protein losses lead to decreased piglet growth rate, lower milk protein concentration and impaired sow ovarian function. Since a lower dietary crude protein level is needed because of environmental concerns, the utilization of dietary protein is crucial to address the problem. Amino acid utilization in the postprandial period depends not only on the ileal amino acid digestibility, but also on the amino acids release rate from the gut, known as the digestion kinetics. Thus, the current study aims to investigate the effects of the protein levels and protein digestion kinetics in the lactation sow diet on postprandial amino acid utilization, sow body condition losses, litter weight gain during lactation and subsequent sow reproductive performance.