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Cottonseed meal is a protein-rich ingredient that could potentially replace traditional animal protein supplements, but its use is limited due to anti-nutritional factors like free gossypol.
Objective: This study tested a cottonseed protein isolate made from cottonseed meal through alkaline extraction and acid precipitation, to see if it improves nutrition and gut health in growing pigs.
Methods: The experiment used a completely randomized design with 32 castrated male Duroc-Landrace-Yorkshire pigs (initial weight 19 ± 2 kg). They were randomly assigned to four diet groups, each with 8 pigs: a nitrogen-free diet, a standard corn–soybean meal diet, a cottonseed meal diet where cottonseed meal replaced 35% of the nitrogen in the corn-soybean meal diet, and a cottonseed protein isolate diet where cottonseed protein isolate replaced 35% of the nitrogen in the corn-soybean meal diet. Researchers measured average daily gain, average daily feed intake, and the gain-to-feed ratio to evaluate performance. The study was conducted over 14 days where pigs were individually housed in metabolic cages to closely monitor intake and outputs. For the digestion and metabolism phase, feed intake was controlled and set at each pig’s average pre-feeding intake to allow precise measurement of nutrient digestibility and metabolism under steady feeding conditions.
Results: Pigs fed with cottonseed protein isolate improved the gain-to-feed ratio by about 8% compared to cottonseed meal-fed piglets and increased crude protein digestibility by over 10%. It significantly enhanced apparent ileal digestibility and standardized ileal digestibility of amino acids like arginine, aspartic acid, glutamic acid, and serine by up to 15%. Cottonseed protein isolate feeding also increased villus height and villus-to-crypt ratio in the duodenum and jejunum and boosted digestive enzyme activities (maltase, α-amylase, and sucrose) in the small intestine. The cottonseed protein isolate diet also increased short-chain fatty acid levels in the cecum and colon and increased the relative abundances of Lactobacillus levels in the colon compared to cottonseed meal. Growth performance and serum biochemical parameters were like those on a standard corn-soybean diet.
Conclusion: Overall, cottonseed protein isolate not only had better nutritional quality than cottonseed meal but also supported growth and gut health, making it a promising alternative to common protein sources like soybean meal.
Wang K, Ren K, Luo Y, Zheng P, Mao X, Yan H, Wang Q, He J. Improved quality of cottonseed meal: effect of cottonseed protein isolate on growth performance, nutrient digestibility, and intestinal health in growing pigs. Journal of Animal Science. 2025; 103:skaf057. https://doi.org/10.1093/jas/skaf057