Effect of diets containing whole white lupin seeds on rabbit doe milk yield and milk fatty acid composition as well as the growth and health of their litters1

Abstract

The effect of dietary inclusion of white lupin seed (WLS) on the milk composition and yield of rabbit does as well as the performance of their litters was studied. Two lactation diets having identical digestible protein (DP):DE ratio and two weaning diets having identical DP:DE ratio were formulated. The first lactation diet (SL) contained soybean meal (SBM; 13.0%) and sunflower meal (5.0%) as the main CP sources, whereas the second lactation diet (LL) was based on WLS (25.0%). As a result, the LL diet had a greater ether extract (EE) content than did the SL diet. The first weaning diet (SW) included SBM (7.0%) as the main CP source, whereas the second weaning diet (LW) diet was based on WLS (12.0%). No additional fat was added to any of the diets. A total of 32 (16 per treatment) Hyplus PS 19 does (4,225 ± 607 g BW, at the second parturition) were fed 1 of the 2 lactation diets. The litters were standardized to 9 kits (564 ± 81 g BW) on the day of birth and were fed 1 of the 2 weaning diets from d 17 to 69 of age. At d 30 of age (weaning), 66 rabbits on each weaning diet (689 ± 71 g BW; 3 per cage) were used to evaluate performance. Feed intake and doe BW were not affected by the dietary treatments. Milk yield tended to be higher between d 1 and 30 of lactation in does fed the LL diet (P = 0.094), a finding that is related to the higher dietary EE content and intake in the LL diet. When expressed per kilogram of metabolic weight, milk output (P < 0.05) and fat output (P < 0.05) were greater in these does. Improved G:F (P < 0.05) between d 1 and 21 of lactation and greater ADG (P = 0.072) and milk efficiency (P < 0.05) of litters was observed in does fed the LL diet. The milk of does fed the LL diet contained less linoleic acid (P < 0.05) and arachidonic acid (C 20:4n-6; P < 0.05) and more oleic acid (P < 0.05), α-linolenic acid (P < 0.05), and eicosapentaenic acid (P < 0.05), with a corresponding increase in the total PUFA n-3:C 20:4n-6 ratio (P < 0.05). The performance of fattening rabbits was not affected by dietary treatment. The number of ill plus dead rabbits caused by digestive disease was lower (P < 0.05) in rabbits fed the LW diet. Therefore, WLS is a suitable dietary CP source for lactating does that can replace traditionally used CP sources without adverse effects on feed intake and milk yield or on the growth and viability of their litters. Due to its fatty acid (FA) composition, the use of WLS in the lactation diet has the potential to improve the milk FA composition of does.