Effects of Pelleting and Long-Term High-Temperature Stabilization on Vitamin Retention in Swine Feed

Simple Summary Pelleting of animal feeds has been practiced for decades, to denature protein, increase starch gelatinization, decrease anti-nutrient factor content, and improve the nutritional value of feed ingredients. Long-term high-temperature stabilization after pelleting has been employed by feed manufacturers to control the spread of pathogenic microorganisms, especially African swine fever through feed. However, pelleting is an aggressive process against vitamins, and prolonged high temperatures may further damage the vitamins' structure. Our results showed that the recovery of vitamin A, vitamin E, vitamin B-2, and vitamin B-6 significantly decreased after pelleting and long-term high-temperature stabilization, and the high-temperature stabilization process has the most significant influence. The objective of this study was to study the effect of pelleting and long-term high-temperature stabilization on the retention of vitamin A, vitamin E, vitamin B-2, and vitamin B-6 in swine feed. Piglet diets (diet 1 and 3) were pelleted after conditioning at 83 degrees C for 120 s, and were high-temperature stabilized at 90 degrees C for 8.5 min after pelleting; the finishing pig diets (diet 2, 4, and 5) were pelleted after conditioning at 82 degrees C for 90 s, and were high-temperature stabilized at 85 degrees C for 9 min after pelleting; the samples were obtained before condition, after condition, after pelleting, and after cooling. The contents of vitamin A and vitamin E in diets 1-5 and vitamin B-2, and vitamin B-6 in diets 3-5 were detected. The results showed that: (1) the conditioning process had no significant effect on the retention of vitamin A, vitamin E, vitamin B-2, and vitamin B-6 in all experimental diets (p > 0.05); (2) the pelleting process and high-temperature stabilization process after pelleting had different degrees of influence on vitamins, among which the stabilization process had a more significant effect on the retention of vitamins. After pelleting and long-term high-temperature stabilization, the retention of vitamin A, vitamin E, and B-2, and vitamin B-6 were 68.8-77.3%, 56.9-90.1%, 63.8-70.3%, and 60.1-67.0%, respectively. In the process of pelleting and long-term high-temperature stabilization, the retention of vitamin A, vitamin E, vitamin B-2, and vitamin B-6 in the feed were significantly reduced (p < 0.05). Therefore, vitamin loss during high temperature and over a long period of time is worth considering, and vitamins must be over-supplemented.