The aim of the study was to assess the effects of the sire genotype, sex and carcass part on the composition of the meat of rabbits, which were fattened under conditions where no synthetic drugs were used. As for carcass parts, the higher content of both total amino acids (AA) and all essential AA (EAA) monitored was found in the Longissimus thoracis et lumborum (LTL) muscle as compared to hind leg meat (p ˂ 0.001). Significant effects of the rabbit sire genotype and the genotype x sex interaction on proportions of some AA in meat were found (p ˂ 0.001). Crossbreeding of the Mecklenburger Schecke (MS) sires with a commercial dam line of HYLA rabbits resulted in a lower proportion of the total AA and all EAA monitored in meats of MS sired males as compared to MS sired females and HYLA rabbits (p ˂ 0.05). The sex-related effect on AA profile was not so noticeable in final commercial crossbreds of HYLA rabbits when compared to MS sired progeny. These findings point to a possible risk of alterations in the nutritional quality of meat proteins when using different rabbit sire genotypes than those originally intended for the specific commercial crossbreeding scheme. However, on the contrary, higher contents of magnesium (p ˂ 0.05), manganese (p ˂ 0.001) and zinc (p ˂ 0.05) were found in meats of MS sired progeny as compared to HYLA rabbits.

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic

The objective of this study was to investigate whether melamine (MEL) is biotransformed into cyanuric acid (CYA) in male broiler chickens. The effects of the dietary addition of MEL and CYA alone and in combination on the growth performance and mortality of the chickens were also investigated. The chickens were divided into six experimental groups and were fed diets with an addition of 50 or 100 mg/kg MEL or 50 or 100 mg/kg CYA of diet, with the contaminants added separately or in combination. The control group was fed a diet without MEL or CYA. At the end of the experiment (day 40), samples of liver, kidney and breast and thigh muscles were collected from 12 birds per treatment group and were analysed for the presence of MEL and CYA. This study showed that MEL is biotransformed into CYA in broilers. Higher concentrations of MEL or CYA in the diet increased the presence of their residues in tissues, and the CYA residue concentration was several times higher in the respective tissues than the MEL residue concentration. The dietary addition of MEL and CYA did not affect the mortality rate, feed conversion ratio or body weight of the chickens.

The aim of the experiment was to define the effect of a Suffolk-sired genotype on the chemical composition and fatty acid profile of the Quadriceps femoris muscle in fattened lambs reared under organic farming conditions. Three different genotypes of Suffolk-sired crossbreds were included in the experiment: F1 Suffolk-Charollais (SF 50 CH 50, n=10), F11 Suffolk-Charollais (SF 75 CH 25, n=10) and F1 Suffolk-Improved Walachian (SF 50 IW 50, n=10). The genotype did not have any effect on age at slaughter, average daily gain or carcass dressing percentages. However, the SF 75 CH 25 lambs displayed a lower live weight at slaughter (P<0.05), lower cold carcass weight (P<0.05) and lower protein content in muscle (P<0.05) than both of the other genotypes. They also had a lower content of kidney fat compared to the SF 50 CH 50 (P<0.01). The F11 Suffolk-Charollais lambs showed a higher proportion of C12:0 (P<0.01), C14:0 (P<0.01) and C16:0 (P<0.05) than the other two genotypes. A higher proportion of C18:0 was found in the SF 50 CH 50 lambs (P<0.05). The total content of saturated fatty acids (SFA) was higher in the SF 75 CH 25 crossbreds (P<0.05). The genotype also affected the content of C16:1 having its highest presence in the SF 75 CH 25 lambs while the lowest presence was found in the SF 50 CH 50 lambs (P<0.01). Between these two genotypes there were also found different proportions of C18:1 having its higher presence in SF 50 CH 50 lambs (P<0.05). Moreover, the IW type lambs had a lower SFA proportion and lower values of atherogenic and thrombogenic indexes and a higher polyunsaturated/saturated fatty acid (P/S) ratio in their meat than lambs of the CH genotypes (P<0.05). As for crossing between the Suffolk and Charollais breeds, a favourable fatty acids profile of meat was observed in the F1 crossbred as compared to the F11 crossbred.