Effect of dietary protein level during gestation period in female minks

Abstract

180 female minks were assigned randomly to 6 groups with 30 females each. Group 1 to Group 4 received diets of fresh material with protein level of 31.79%, 36.53%, 41.39% and 45.39% respectively. Group 5 to Group 6 received diets of dry powder with protein level of 36.55%, 44.47% respectively. The results were as follows: In groups fed fresh material diet, CP digestibility, EE digestibility, nitrogen deposition, NPU and BV increased with dietary protein level(R² were 0.9811, 0.9531, 0.9047 and 0.8532, respectively). Indicators mentioned above reached the peak when protein level was 45.39% (P>0.05).No significant difference was observed in DM digestibility and EE digestibility in fresh material diet fed groups. Compared with groups fed fresh material diet of same dietary protein level, the dry powder ones showed significantly lower values in DM digestibility, CP digestibility, EE digestibility, nitrogen deposition, NPU and BV (P<0.05). Different dietary protein levels showed no significant difference in mating rate, parturition rate, litter size, number of born alive, birth survive rate, Individual birth weight among fresh material fed groups, but parturition rate, litter size, number of born alive firstly increased and then decreased with increasing dietary protein level, reaching the peak at 36.53% dietary protein level. Mating rate, parturition rate, litter size, number of born alive, birth survive rate, individual birth weight decreased or significantly decreased in groups fed dry powder diet compared with groups fed flesh material diet of same protein level (P<0.05).The results showed that the optimum dietary protein level in gestation period was approximate 36%.