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.

The aim of this study was to determine the effect of full-fat Hermetia illucens (HI) larvae meal used as a substitute for 50%, 75% and 100% of soybean meal (SBM) in diets fed to male Ross 308 broiler chickens on the proximate chemical composition and fatty acid profile of the Pectoralis major (PM) muscle. The muscles of chickens fed HI larvae meal were characterized by a higher (p < 0.05) total concentration of pigments and lower (p < 0.05) ash content. At the lowest dietary inclusion rate (50%) of HI larvae meal, the PM muscle had a lower (p < 0.05) content of fat and collagen, compared with the remaining treatments. An analysis of the fatty acid profile of the PM muscle revealed that the total concentrations of saturated fatty acids increased (p < 0.05) and the total concentrations of polyunsaturated fatty acids decreased (p < 0.05) with increasing inclusion levels of HI larvae meal. The changes in the fatty acid profile of muscles in birds receiving HI larvae meal led to a decrease in the nutritional value of fat. The present findings indicate that the ≥50% inclusion rate of full-fat HI larvae meal as a protein source alternative to SBM in broiler chicken diets is too high due to its negative effect on the fatty acid profile of meat.

The aim of this study was to compare selected physical (density) and physicochemical (color, pH, titratable acidity) properties and the fatty acid profile of dairy UHT milk and its plant-based analogs, i.e., almond, soy, rice, oat, and coconut beverages. Ten products of each type were analyzed in each group. UHT milk was characterized by higher values of color lightness (L*) and titratable acidity than all plant-based milk alternatives, higher yellowness (b*) than rice drink, higher density than almond drink, and higher pH than rice and coconut drinks. In comparison with UHT milk, all plant-based beverages were characterized by higher redness (a*), soy drink was characterized by higher values of b* and chroma (C*), and almond and soy drinks had higher pH values. In the group of non-dairy beverages, the values of b* and C* were highest in soy drink, and the value of a* was highest in almond drink. Almond drink had the highest pH value, and soy and coconut drinks had the highest titratable acidity. Rice drink had higher density than oat, soy and almond drinks. The indicators characterizing the nutritional value of fat were considerably lower in coconut drink and dairy milk than in the remaining products. The values of UFA/SFA, MUFA/SFA, and DFA/OFA ratios and the indicator of nutritional value were highest in rice drink. The PUFA/SFA ratio and the total content of EFAs were highest in soy drink, and the n-6/n-3 PUFA ratio was highest in almond drink.

The surgical castration of male chickens induces hormonal changes, which permanently influence metabolic processes in birds. The aim of this study was to determine the effect of age and castration on the growth rate, feed conversion, lipid profile and histopathological changes in the livers of cockerels and capons. The experimental materials comprised male chickens of the Green-legged Partridge breed (old traditional Polish chicken breed), raised to 28 weeks of age. At 8 weeks of age, 100 birds were castrated. Caponization had a significant effect on the plasma concentrations of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and triacylglycerols (P<0.05). Fatty degeneration and lymphoid cell infiltration were observed more frequently in the livers of capons than cockerels. Capon carcasses were characterized by increased deposition of abdominal and subcutaneous fat (P<0.05). Total meat weight in the carcasses of cockerels and capons was similar, but the proportions of muscles were different. From 20 weeks of age, the weight of breast muscles was higher, and the weight of leg muscles was lower in capons than in cockerels (P<0.05). Capons were characterized by higher liver weight, higher gizzard weight and lower heart weight than cockerels (P<0.05). The feed conversion ratio (kg/kg BW) was similar in intact cockerels and capons. The values of carcass quality parameters and feed conversion ratio as well as histopathological changes in the liver indicate that Green-legged Partridge capons should be slaughtered at 20 to 24 weeks of age.

The preference of modern consumers for high-quality meat has forced breeders to use native breeds to produce capons. Caponization, both chemical and surgical, leads to androgen deficiency and changes in lipid metabolism and results in the accumulation of abdominal, subcutaneous, and intramuscular lipids, which change the sensory values of the meat. The aim of this study was to histologically evaluate selected skeletal muscles from Greenleg Partridge capons and cockerels. We examined lipid localization in the muscular tissue and also assessed both fiber type and fiber diameter in the pectoral muscles. The experiment was performed on 200 Greenleg Partridge cockerels and testes were removed at 8 wk of age. At 12, 16, 20, 24, and 28 wk of age, 6 cockerels and 6 capons were slaughtered, and samples from the pectoral and thigh muscles were evaluated. Our histopathological evaluation revealed only minimal changes, and no significant differences between capons and cockerels were observed. The pectoral and thigh muscles of the capons had higher concentrations of lipids around the blood vessels, in the perimysium, in the endomysium, and in the sarcoplasm. The analysis of fiber type in the Pectoralis major muscles revealed that the fibers were all the IIB type. The diameters of the fibers of the pectoral muscles were significantly different (P < 0.05) at 20, 24, and 28 wk of age, and diameters of the giant fibers were significantly different (P < 0.05) at 24 and 28 wk of age. High concentrations of lipids in the meat of the capons is undesirable due to health-related reasons. However, the ability of adipose tissue to improve the sensory values of meat will always be a major quality of native/traditional products.

Age has a significant effect on carcass tissue composition, which is an important consideration in slaughter animals because age-related changes are