Grain grinding size of cereals in complete pelleted diets for growing lambs: Effects on ruminal microbiota and fermentation

Abstract

Lambs from intensive dairy sheep production systems are sold out either after weaning as milk-fed lambs or after a fattening characterized by high intakes of concentrate feeds (mainly cereals) which can lead to ruminal disorders. Therefore, it is essential to explore different feeding alternatives in order to reach a balance between economic or productive benefits and animal welfare. Twenty weaned male lambs (6 to 8 weeks age, 14.8 ± 0.16 kg body weight) were allocated randomly to one of two different groups (n=10 per group) to study the effect of feeding a complete pelleted diet (CPD) in which cereal grains were ground at two different sieve sizes (either 2-mm with 13.5% dry matter (DM) of the particles > 1.7 mm or 6-mm with 47.1% DM of particles > 1.7 mm) on DM intake, nutrient digestibility, ruminal microbiota and fermentation. Lambs were fed the corresponding CPD ad libitum and slaughtered when they reached 27 kg. DM intake was greater in the lambs fed 2-mm grains than in those fed 6mm grains (P<0.05). Feeding 2-mm grains in comparison to 6-mm grains resulted in darker colour of ruminal mucosa (100 vs. 127, from a scale where 0 is black and 256 white; SED=9.8; P=0.017) and thicker stratum corneum (45.3 vs. 30.9 µm; SED=3.67; P=0.001), suggesting more severe acidotic conditions in the rumen with the smaller cereal particle size. Analysis of microbial communities revealed that the presence of ruminal bacteria such as Prevotella and Quinella, were increased in the digesta of animals fed the 2-mm diet. These data were corroborated by the odd-and branched-chain fatty acid profile of ruminal contents, which would indicate a shift from cellulolytic to amylolytic bacteria in the rumen of lambs fed the 2-mm diet. In conclusion, feeding 6-mm in comparison to 2-mm ground cereal grains included in CPD formulated for growing lambs is an alternative strategy that may reduce ruminal acidosis through changes in the microbiota.

Feeding Agroindustrial Byproducts to Light Lambs: Influence on Growth Performance, Diet Digestibility, Nitrogen Balance, Ruminal Fermentation, and Plasma Metabolites

“…There was no effect (p ≥ 0.247) of the type of concentrate on post-mortem ruminal pH, total VFA concentrations, molar proportions of individual VFA, or acetate/propionate ratio (Table 4). The pH values and acetate/propionate ratios were similar to those reported for lambs fed high-cereal concentrates and straw [13,26,31,32]. The lower (p = 0.003) NH 3 -N concentrations in the rumen of BYP-fed lambs compared with control-fed lambs might indicate lower CP degradability in the BYP-concentrate.…”

Astragalus membranaceus Alters Rumen Bacteria to Enhance Fiber Digestion, Improves Antioxidant Capacity and Immunity Indices of Small Intestinal Mucosa, and Enhances Liver Metabolites for Energy Synthesis in Tibetan Sheep

“…In contrast, an increase in the relative abundance of Prevotella has been observed in the rumen of cattle facing acidotic challenge [ 33 ] and an increase in both Prevotella and Quinella has been reported in Holstein cows with severe ruminal acidosis [ 32 ]. Quinella is well adapted to acidotic conditions [ 34 ]; consequently, the reduction in Quinella with supplementary AMT at 50 and 80 g/kg DMI indicated a non-acidotic rumen condition.…”

Effects of forage rape at various levels on growth performance, carcass traits, meat quality, rumen fermentation and rumen microbiota of Hu lambs

“…Quinella is a propionate-producing bacterium [19]. Some members of the genus Quinella were found in the rumen of sheep and steers fed diets with molasses, and the presence of Quinella was increased in growing lambs with ruminal acidosis caused by smaller grinded grains [20]. The functional role of Quinella in the rumen fermentation of group Ctrl are yet to be explored.…”