DIETARY SUPPLEMENTATION OF SPIRULINA (Arthrospira platensis) AND THYME (Thymus vulgaris). PART 4: EFFECT ON RABBIT CARCASS AND MEAT QUALITY

The aim of the study was to evaluate the effect of the dietary supplementation of 5% Spirulina (S) and 3% Thyme (T) leaves and the length of their supplementation on carcass traits and meat quality of fattening rabbits. Maternal line rabbits (n=294) of both sexes were used. S and T were supplemented to isonitrogenous and isoenergy diets formulated to cover the requirements of meat producing rabbits. All diets did not include coccidiostatic. Rabbits received the S and T supplementation separately or combined (TS), during the whole growing-fattening period (5th-11th week of age: S-S; T-T; ST-ST) or only during fattening (8th-11th week of age: C-S; C-T; C-ST). On overall 7 groups of animals of 36 rabbits each were used for carcass evaluation: Control (C-C; not supplemented diet) C-S, S-S, C-T, T-T, C-ST, ST-ST. Rabbits were slaughtered at 77 days of age. Carcasses were dissected and carcass yield, carcass fatness and meatiness were determined and pHu and L*a*b* colour were measured on Longissimus dorsi (LD) muscle. On 15 rabbits per dietary treatment the LD muscle was dissected and frozen for WHC, proximate composition, cholesterol, heme iron and vitamin B12 analyses on raw meat and for proximate composition and cholesterol content on cooked meat. Carcass traits were not affected by the dietary treatments, with exception of the incidence of the scapular fat that showed its lowest value in C-T group (0.39%) and its highest value in S-S (0.56%; P<0.05). Spirulina and Thyme supplementations didn’t affect the rheological traits as well, even though a tendency towards a lower total water loss was found in S-S and C-S groups (33.1 and 33.4%, respectively; n.s.) compared to the other groups (35.2±0.86 %). Consequently, cooked LD meat of S-S group contained more water (67%) than the other groups (66.1±0.27 %; n.s.). S-S and T-T diets reduced the protein content in the cooked LD meat, compared to the C-C diet (31.3 and 31.5 vs 32.4%; P=0.051), and cholesterol content was found the lowest in S-S group, both in raw and cooked LD meat (49.7 and 76.0 mg/100 g). In this study the effect of Spirulina supplementation as lipid lowering wasn’t confirmed. Based on our results, Spirulina supplement seems promising in enhancing WHC and vitamin B12, and in reducing cholesterol content of rabbit meat, but its inclusion level should be further increased.