Jürgen Hummel

To keep up with increasing demand for animal protein, alternative protein sources will need to be included in current animal production systems. The efficient growth of Hermetia illucens larvae combined with municipal waste as a substrate has the potential to increase the sustainability of protein feed production. Therefore, this study partially substituted soymeal with H. illucens larval meal (reared on municipal waste) in broiler diets to determine the effect on slow-growing broiler (ISA-JA-757 and Les Bleues) production. Growth and slaughter performance, as well as animal welfare and meat quality parameters were evaluated. No influence of H. illucens larvae meal in the diet was found for weight gain, feed efficiency and slaughter performance. Animal welfare was also not influenced by diet. Fatty acid composition of intramuscular fat was influenced by the inclusion of H. illucens in the broiler diets; however not uniformly across meat cut. Differences between animal genotype and animal sex often influenced parameters under investigation more than diet itself. Overall, H. illucens can be regarded as a suitable protein source in slow-growing broiler diets.

Sheep with a relatively low methane yield were observed to have shorter fluid and particle mean retention times (MRT). Because the application of pilocarpine, a saliva stimulant, was successful in reducing retention times in ruminants in previous studies, we applied this substance to sheep, expecting a reduction in MRT and methane yield. Three non‐pregnant sheep (74 ± 10 kg) were fed a hay‐only diet in a 3 × 3 Latin square design with oral doses of 0, 2.5 and 5 mg pilocarpine/kg body weight and day. Measurements included feed and water intake, MRT of liquid and particulate phases in the reticulorumen (RR) and total gastrointestinal tract (GIT), ruminal microbial yield (via urinary purine bases and metabolic faecal nitrogen), total tract methane emission, apparent nutrient digestibility and rumen fluid parameters. Data were investigated for linear and quadratic effects using orthogonal polynomial contrasts. The MRT of liquid and small particles in the RR and total GIT, and the short‐chain fatty acid concentration in rumen fluid, linearly declined with increasing pilocarpine dosage, while no quadratic relationship was detected. Intake of feed DM and water, apparent nutrient digestibility, methane yield and microbial yield were not affected by pilocarpine. When combining the sheep data with that of a similar experiment in cattle, we found that the MRT of the liquid phase was positively associated with estimated NDF digestibility and with methane production per digested NDF, but was not associated with microbial yield or the ratio of acetate to propionate. The ratio between MRT of the particulate and the liquid phase was smaller for sheep than that for cattle, and was not affected by treatment. Differences in this ratio might explain why species reacted differently to the saliva‐inducing agent, which might help to explain the discrepancy between species in the effect of induced saliva flow on digestive parameters.