Fermented feed from lotus seedpod alleviates the impact of heat stress on beef cattle in summer

Abstract

A large amount of lotus seedpod (LSP) is generated every year during the production of lotus seeds, and most of them are wasted. A green approach for processing LSP is required. The study aimed to convert LSP into value-added product (FLSP) through solid-state fermentation, and investigate the effects of FLSP on rumen fermentation and heat stress on beef cattle under high temperature conditions in summer by in vitro and in vivo methods. Results showed that the contents of crude fiber and total tannin in FLSP were decreased by 23.65% and 39.58%, respectively, while the levels of crude protein, crude fat and total polysaccharide were increased by 27.41%, 29.03% and 20.89%, respectively, after silage fermentation. Addition of 50%-75% FLSP to the in vitro rumen fermentation substrate was found to improve fermentation characteristic parameters, such as gas production, microbial crude protein, ammonia nitrogen, dry matter digestibility, and volatile fatty acid levels. Addition of 20%-60% FLSP to the diet of beef cattle significantly alleviated the symptoms of heat stress, such as reduced appetite, rapid breathing and lethargy on beef cattle in summer. The average daily weight gain of beef cattle was 1.30%-11.63%, and the dry matter intake increased by 1.44%-3.15%. The levels of the heat stress-related hormone cortisol were reduced by 2.66%-17.51%, and the levels of triiodothyronine and tetraiodothyronine hormones were increased by 0-14.07% and 13.31%-23.72%, respectively. These results suggest that FLSP can be used as a feed for ruminants and has the function of alleviating heat stress reactions under high temperature conditions.