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By-products of biofuels production such as rapeseed cake and dried distillers' grains with solubles (DDGS) may constitute valuable feedstuffs for livestock. The objectives of the study were to determine the usability of these components in the feeding of growing rabbits and to assess their impact on physiological changes in the gastrointestinal tract of the animals. Sixty-four rabbits were divided into four feeding groups: Control (5% soyabean meal [SBM] in the diet), R (5% rapeseed cake [RSC]), DDGS (5% wheat DDGS), and R/DDGS (2.5% RSC and 2.5% wheat DDGS). The study included a production experiment, a digestibility-balance experiment and physiological assessment of the functioning of animals' gastrointestinal tract (small intestine, caecum and colon). No statistically significant differences were determined in production results of the rabbits. Digestibility of nutrients and energy and nitrogen retention were the highest in the Control and the lowest in Group DDGS. Group DDGS was characterised by the highest relative weight of small intestine and digesta. In turn, Group R was characterised by the highest degree of caecal digesta hydration and bulking and by the highest pH value and the lowest concentration of VFA in caecum. The activity of selected bacterial enzymes released to the caecal environment was similar in all groups; however, the activity of α-arabinopyranosidase was significantly increased in Groups R and DDGS. Worthy of notice is the enhanced enzymatic activity of colonic microbiota in the R/DDGS group which has a positive effect upon increased utilisation of dietary nutrients compared to the DDGS group. The obtained results indicate that SBM from rabbit diets may be successfully replaced by 5% RSC as well as by 2.5% RSC + 2.5% wheat DDGS.

Forty New Zealand White rabbits weaned at 30 d were divided into 2 groups and reared under intensive or extensive production system until slaughter (91 d of age). In the extensive production system, rabbits were housed in free-standing cages on straw litter and fed farm-made feed ad libitum. Control rabbits were raised intensively in wire mesh slatted floor cages, indoors and on a commercial pellet ad libitum. Hot carcass weight was 16,6% lower (P<0.01) in extensive production. The difference of 1 point both in hot and cold dressing percentage in favour of the intensively reared rabbits was not significant (P>0.05). The higher carcass weight of the control rabbits led to heavier primal cuts, including head (P<0.05) and the fore part, intermediate part and hind part of the carcass (P<0.01). However, expressed as % of carcass weight, significantly higher ratio were only found for the head (P<0.01) and edible offal (P<0.05) in intensively produced rabbits. The production systems investigated had no significant (P>0.05) effect on the chemical composition, physicochemical properties and organoleptic characteristics of meat from New Zealand White rabbits.

The aim of this study was to compare selected growth performance parameters and slaughter characteristics in broiler chickens fed diets with a different content of full-fat Hermetia illucens L. (HI) larvae meal. The experiment was performed on 384 male broiler chickens (Ross 308) reared to 42 d of age and assigned to four dietary treatments (HI0—control diet and diets where soybean meal protein (SBM) was replaced with HI protein in 50%, 75% and 100%, respectively). The final body weights of chickens were as follows: 3010.0 g (HI0), 2650.0 g (HI50), 2590.0 g (HI75) and 2375.0 g (H100, p < 0.05). The carcasses of chickens from the experimental groups contained less meat and more abdominal fat. The feed conversion ratio for the entire experimental period was similar in groups HI0, HI50 and HI75 and more desirable than in group HI100 (p < 0.05). The meat of broiler chickens from groups HI75 and HI100 was characterized by significantly (p < 0.05) lower juiciness and taste intensity than the meat of birds from groups HI0 and HI50. The replacement of SBM protein with full-fat HI larvae meal in broiler diets exceeding 50% significantly compromised the growth performance of birds and the carcass and meat quality.