Combined feeding of rabbit female and young: Partial replacement of starch with acid detergent fibre or/and neutral detergent soluble fibre at two protein levels

Abstract

To evaluate the effects of the composition of weaning diets used for combined feeding both on the performance and body condition of rabbit does and on the growth and health of young rabbits, eight experimental diets were formulated according to a factorial design 2×2×2, the three factors being: i) partial replacement of starch with acid detergent fibre (ADF), ii) partial replacement of starch with neutral detergent soluble fibre (NDSF) and iii) reduction of the crude protein (CP) content from 175 to 145g kg−1 dry matter (DM). The study involved 138 rabbit does and 318 litters fed experimental diets from 17th to 28th day of lactation (weaning). Thereafter, 2371 weaned rabbits (784 in individual cages and 1587 in collective ones) continued receiving the same experimental diets until 49days of age and a commercial finishing diet until 60days of age. Replacing starch with ADF increased feed intake of does (+26±5g DM day−1, P<0.001) but, only with high CP diets, impaired their milk yield (−15±6g day−1, P<0.01) and perirenal fat thickness (PFT) change (−0.41±0.13mm, P<0.01), as well as litter weight at weaning (−154±52g, P<0.01); from weaning to 49days of age, this replacement increased feed intake (+14±2g DM day−1, P<0.001) and impaired live weight gain (−1.6±0.7g day−1, P<0.05), but reduced mortality rate (−10.2%, P<0.001). Replacing starch with NDSF reduced feed intake of does, in greater extent with high CP diets (−34±6g DM day−1, P<0.001) than with low CP diets (−19±7g DM day−1, P<0.01), as well as their milk yield (−16±4g day−1, P<0.001), with impairing PFT change only with high CP diets (−0.30±0.13mm, P<0.05); litter feed intake and weight at weaning were also negatively affected (−14.4±2.5g DM day−1, −202±38g, P<0.001); from weaning to 49days of age, this replacement reduced feed intake (−8±2g DM day−1, P<0.001), impaired live weight gain only with low CP diets (−2.3±1.0g day−1, P<0.05) and reduced mortality rate (−15.1%, P<0.001). Reducing CP content affected negatively feed intake of does (−22±5g DM day−1, P<0.001), as well as their milk yield, this impairment being more important with more starch–less ADF diets (−24±5g day-1, P<0.001) than with less starch–more ADF diets (−13±6g day−1, P<0.05), and, only with more starch–less ADF diets, PFT change (−0.36±0.13mm, P<0.01); litter feed intake was affected negatively (−20.1±2.4g DM day−1, P<0.001), as well as litter weight at weaning, in great extent when fed more starch–less ADF diets (−581±52g, P<0.001) than when fed less starch–more ADF diets (−403±54g, P<0.001); from weaning to 49days of age, this dietary change reduced feed intake (−6±2g DM day−1, P<0.001) and impaired live weight gain (−5.0±0.7g, P<0.001), but reduced mortality rate (−19.9%, P<0.001). Overall, the three dietary changes under study impaired milk yield, body condition of does and litter weight at weaning, although the negative effect of replacing starch with ADF was only observed in the high CP diets; moreover, growth during post-weaning period also decreased. However, in an Epizootic Rabbit Enteropathy context, mortality rate during this period was reduced by these three dietary changes, which effects seemed additive.