Resumen de Effects of replacement of alfalfa by big-leaf mulberry on growth performance, digestion and meat quality in growing rabbits

Zhuang Xue Wu, Long Pei Yang, Hua Xiu Gao, Guo Zhi Wen, Fa Si Dai, Xia Ming Zhu, Xin Li Wang

• This study aimed to investigate the effect of sundried big-leaf mulberry (BLM) as a replacement for alfalfa on the growth performance, digestibility of nutrients, nitrogen (N) utilisation and meat quality in New Zealand White rabbits. One hundred and sixty weaned rabbits, aged 35±1 d and with a body weight of 755±26 g, were randomly assigned to the 4 treatments with 20 replicates of 2 rabbits (1 male and 1 female) each. Animal performance was evaluated between the 35th and 77th d of age in 40 animals per treatment. The coefficients of total tract apparent digestibility (CTTAD) of nutrients and N utilisation were measured between 77 to 83 d of age in 30 animals per treatment. The control rabbits were fed a corn-soybean meal-alfalfa meal based diet. The three experimental groups were fed a similar diet in which the alfalfa meal was replaced by 10% (BLM10), 20% (BLM20), or 30% (BLM30) BLM. The final body weights and average daily gain were higher (P<0.05) in BLM20 rabbits compared to control and BLM30 rabbits. Although BLM inclusion had no effects on the CTTAD of dry matter, organic matter and crude protein (P>0.10), the CTTAD of ether extract was higher in rabbits fed the diets based on BLM (P<0.05). No effect of treatment was noted on ingested and faecal N. Urinary (P<0.05) and retained N (P<0.10) were higher in animals fed with BLM30 and BLM20 diets, respectively. Dietary BLM supplementation increased a* (P<0.05) and tended to reduce L* (P<0.10) in rabbit meat samples. It was concluded that replacing alfalfa meal with BLM (20%) can promote growth and increase ether extract digestibility. Additionally, dietary BLM supplementation can increase the redness value of meat.