Nutritional impact on health and performance in intensively reared rabbits

The present work summarizes research related to the definition of nutrient recommendations for feeds used in the intensive production of rabbit's meat. Fibre is the main chemical constituent of rabbit diets that typically contain 320 to 360 and 50 to 90 g/kg of insoluble and soluble fibre, respectively. Instead, the dietary contents of cereal grains (∼120 to 160 g/kg), fat (15 to 25 g/kg) and protein concentrates (150 to 180 g/kg) are usually low with respect to other intensively reared monogastric animals. Cell wall constituents are not well digested in rabbits, but this effect is compensated by its stimulus of gut motility, which leads to an increasing rate of passage of digesta, and allows achieving an elevated dry matter intake. A high feed consumption and an adequate balance in essential nutrients are required to sustain the elevated needs of high-productive rabbits measured either as reproductive yield, milk production or growth rate in the fattening period. Around weaning, pathologies occur in a context of incomplete development of the digestive physiology of young rabbits. The supply of balanced diets has also been related to the prevention of disorders by means of three mechanisms: (i) promoting a lower retention time of the digesta in the digestive tract through feeding fibre sources with optimal chemical and physical characteristics, (ii) restricting feed intake after weaning or (iii) causing a lower flow of easily available substrates into the fermentative area by modifying feed composition (e.g. by lowering protein and starch contents, increasing its digestibility or partially substituting insoluble with soluble fibre), or by delaying age at weaning. The alteration in the gut microbiota composition has been postulated as the possible primary cause of these pathologies.

Influence of source and micronization of soya bean meal on growth performance, nutrient digestibility and ileal mucosal morphology of Iberian piglets

The effects of inclusion in the diet of different sources of soya bean meal (SBM) on growth performance, total tract apparent digestibility (TTAD) and apparent ileal digestibility (AID) of major dietary components and mucosal ileum morphology were studied in Iberian pigs weaned at 30 days of age. From 30 to 51 days of age (phase I), there was a control diet based on regular soya bean meal (R-SBM; 44% CP) of Argentina (ARG) origin and five extra diets in which a high-protein soya bean meal (HP-SBM; 49% CP) of the USA or ARG origin, either ground (990 μm) or micronized (60 μm), or a soya protein concentrate (SPC; 65% CP) substituted the R-SBM. From 51 to 61 days of age (phase II), all pigs were fed a common commercial diet in mash form. The following pre-planned orthogonal contrasts were conducted: (1) R-SBM v. all the other diets, (2) SPC v. all the HP-SBM diets, (3) micronized HP-SBM v. ground HP-SBM, (4) HP-SBM of ARG origin v. HP-SBM of US origin and (5) interaction between source and the degree of grinding of the HP-SBM. Dietary treatment did not affect growth performance of the pigs at any age but from 30 to 51 days of age, post weaning diarrhoea (PWD) was higher (P<0.001) and the TTAD and AID of all nutrients were lower for pigs fed the R-SBM diet than for pigs fed the HP-SBM or the SPC diets. However, no differences between the HP-SBM and the SPC containing diets were detected for any trait. The TTAD of organic matter (P=0.07) and gross energy (GE) (P=0.05) tended to be higher for the micronized HP-SBM than for the ground HP-SBM and that of GE was higher (P<0.05) for US meal than for the ARG meal. Pigs fed R-SBM had lower villus height (P<0.01) than pigs fed HP-SBM or SPC but no differences in ileal mucosal morphology were detected between SPC and HP-SBM containing diets. It is concluded that feeding the HP-SBM or SPC-reduced PWD and improved nutrient digestibility and ileal morphology as compared with feeding the R-SBM, but had no effect on pig performance. The inclusion in the diet of added value soya products (micronized SBM or SPC) in substitution of the R-SBM increased the TTAD of all nutrients and reduced PWD but had no advantage in terms of growth performance over the use of ground HP-SBM.

Effect of sugar beet pulp fibre fractions on growth performance, fecal digestibility and digestive physiology in rabbits around weaning

The present study investigated the effect of the different fibre components of sugar beet pulp (SBP) on growth performance and some digestive traits. Four semi-synthetic diets were formulated with similar NDF (33% DM) and protein (16% DM) level. Control diet was formulated to contain the lowest level of soluble fibre (3% DM) and SBP diet the highest (9%). The soluble (pectins) and insoluble fractions of SBP were studied in other two diets (Pectin and InsSBP diets). A total of 136 weanling rabbits (25 d of age) was housed individually, randomly assigned to 4 experimental groups, and fed ad libitum with the experimental diets during 10 days after weaning. The type of diet did not affect growth rate and stomach pH. Animals fed with SBP diet showed higher DM and NDF digestibility (4 and 83%, respectively), gain:feed ratio (13%), cecal and total tract weight (13 and 9%) and ileal viscosity (148%) than rabbits fed the Control diet, but lower cecal pH (9%). Pectin diet increased ileal viscosity and decreased the weight of stomach content with respect to SBP diet. Rabbits fed InsSBP diet showed similar results to SBP diet but lower ileal viscosity and cecal pH than those fed Pectin diet. In conclusion, SBP and their soluble and insoluble fractions are well digested in young rabbits. However the soluble and insoluble fibre of SBP produce different effects in the gastrointestinal tract.