• Energy Research

SummaryTo find equations able to estimate the fermentation characteristics of the caecum from that of faeces, caecal content and faeces of 10 hybrid Hyla rabbits were used as inocula for an in vitro gas production trial. About 1 g of 12 roughages, 11 hays (ryegrass, alfalfa, sulla, oat, vetch, sulla‐lolium, vetch‐oat, sulla‐oat, clover, ryegrass‐clover, sulla‐vetch‐oat) and a wheat straw, was weighed, in triplicate per inoculum, in 120‐ml flasks; 75 ml of anaerobic medium and 4 ml of reducing solution were added and the flasks were placed at 39 °C. Caecal content and faeces were diluted respectively 1:2 (CI) and 1:8 (FI) with anaerobic medium and were introduced into their respective flasks (10 ml). Gas production was recorded 20 times at 2–24 h intervals throughout fermentation (120 h). The fermentation characteristics (i.e. degraded organic matter, OMd; potential gas production, A; maximum fermentation rate, Rmax; volatile fatty acid, VFA; ammonia, NH3) were studied by inocula and substrates. The two inocula did not differ in OMd but CI produced significantly higher gas (A, 213.1 vs. 199.4 ml/g, respectively, for CI and FI, p < 0.01) in less time (Rmax, 3.08 vs. 2.24 ml/h, respectively, for CI and FI, p < 0.01). CI also produced higher levels of total VFA (57.86 vs. 46.70 mmol/g OM, respectively, for CI and FI, p < 0.01) and showed a higher branched chain proportion (0.023 vs. 0.018, respectively, for CI and FI, p < 0.01). For some parameters (as OMd pH and propionate) the equations for the estimation of caecal fermentation characteristics from that of faeces were accurate (R2 > 0.8828) and reliable (CV < 10.78%) suggesting that faeces can be successfully used for the estimation of these parameters.

The effects of replacement of maize grain with ancient wheat by-products on intestinal morphometry and enzymatic activity in laying hens was studied. Eighty hens were divided into two groups (40 each, 8 replicates, 5 hens/replicate) fed two isoproteic and isoenergetic diets. In the treated group, part of the maize was replaced by a mix of ancient grains (AGs) middling, in a 50:50 ratio of Triticum aestivum L. var. spelta (spelt) and Triticum durum dicoccum L. (emmer wheat). The AG diet affected the weight of all the large intestine tracts, decreasing the weight of caeca (p < 0.01) and increasing those of colon (p < 0.01), rectum and cloaca (p < 0.05). Villus height in the AG group was higher (p < 0.01) than the control for the duodenum and jejunum, while for the ileum, the control group showed the highest values (p < 0.01). The submucosa thickness was higher (p < 0.01) in the control group for the duodenum and ileum, while the jejunum for the AG group showed the highest (p < 0.05) submucosa thickness. The crypts depth was higher (p < 0.01) in the control group for the duodenum and ileum. Enzyme activity was enhanced by AGs (p < 0.01) in the duodenum. Regarding the jejunum, sucrase-isomaltase and alkaline phosphatase had higher activity (p < 0.05 and p < 0.01, respectively) in the AG group. In the ileum, sucrase-isomaltase showed higher activity (p < 0.01) in the control group, while alkaline phosphatase showed the highest values (p < 0.05) in the AG group. Overall, results suggested that the dietary inclusion of AGs exerted positive effects in hens, showing an improved intestinal function.