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The aim of this study was to evaluate the effect of dietary supplementation with spirulina (Arthrospira platensis) or/and thyme (Thymus vulgaris) on total tract apparent digestibility of nutrients and the performance of growing rabbits. At weaning (5 wk of age) the rabbits were randomly allotted to 7 groups (42 rabbits/group, 3 rabbits/cage). Rabbits in the control group (C-C) received a control pelleted feed throughout the experiment (5-11 wk of age) without any supplementation (crude protein: 176 g CP/kg, neutral detergent fibre: 325 g NDF/kg). In the other groups, the control diet was supplemented with 5% spirulina (S, mainly in substitution of soybean meal), or 3% thyme (T, mainly in substitution of alfalfa meal) or by both 5% S and 3% T (ST) for the whole (5-11 wk of age; groups: S-S, T-T, ST-ST) or part of the growing period (8-11 wk of age; groups: C-S, C-T, C-ST). Supplementations had no effect on apparent digestibility of dry matter, organic matter, acid detergent fibre, gross energy and digestible energy. The CP TTAD was lowest in rabbits fed the S diet, whereas it was highest in C fed rabbits, the other 2 treatments being intermediate (P<0.001). The starch TTAD was lowest for S fed rabbits (98.3%) and highest for ST fed rabbits (99.4%), the other 2 dietary groups being intermediate (P<0.001). In contrast, the ether extract TTAD was higher in T than ST and C dietary groups (on av. 70.4 vs. 67.7% respectively; P<0.001), with S fed rabbits showing an intermediate value (69.1%). The NDF TTAD of the ST diet was lower than that of the other 3 groups (16.4 vs. 21.0% respectively; P<0.001). The TTAD of Ca reached the lowest value for the S diet (53.5%) compared with the other 3 diets (on av. 59.1%; P<0.001). The S diet also had the lowest digestibility (P<0.001) for K and P, but in this case the C group always showed the highest values (P<0.001), with T and ST rabbits exhibiting intermediate results. Spirulina and/or thyme dietary supplementation had no effect on feed intake (133 g/d), daily weight gain (38.3 g/d), morbidity (9.9 %) or mortality (1.8 %). Significant differences were only found for feed conversion ratio, which was lower for the C-T group (3.39) than for the C-C group (3.54; P<0.05). Based on these results, spirulina and thyme included separately or combined in growing rabbit diets did not exhibit substantial effects on growth performance or health status.

The aim of the experiment was to study the effect of dam and sire genotypes on the production and slaughter performance of growing rabbits. The experiment was carried out at Kaposvár University. Pannon White (PW) and maternal line (M) does were inseminated with the sperm of PW, M, large body line (LB), terminal line of Hycole hybrid (H), or colored line (CL) bucks. The mature body size of the M, PW, and CL genotypes was medium. The mature body size of the LB and H genotypes was large. Only PW and LB rabbits were selected for carcass traits based on computer tomograph (CT) scanning data. The rabbits (n = 320) were weaned at the age of 5 wk and housed in a closed climate-controlled rabbitry in wire cages. Rabbits were fed ad libitum a commercial pellet. Rabbits were slaughtered at 78 d of age. Daily BW gain (5.7%, P < 0.001) and G:F (6.2%, P < 0.001) of the progeny of PW does were better than those of the progeny of the M does. The weight of the chilled carcass and body parts was greater for the progeny of the PW does (P < 0.001). The ratio of the hind part compared with the reference carcass was greater in the PW group (P < 0.001); however, the ratio of the fore part was greater in the M group (P < 0.05). Examining the effect of the genotype of the sires, the BW and daily BW gain were greater in groups H and LB, whereas the progeny of M and CL sires were inferior (P < 0.05). Body weights at 11 wk of age were H: 2,918 g, LB: 2,793 g, PW: 2,678 g, CL: 2,636 g, and M: 2,585 g (P < 0.001). Similar differences were found for daily feed intake (P < 0.05). The G:F differed (P < 0.05) significantly between groups H and CL. The weights of the chilled carcass and of the body parts were the greatest for the progeny of the H sires, and the smallest in the M group. The differences between the dressing out percentages of the groups were not significant. The ratio of the fore part was greater (P < 0.05) in groups LB, H, and CL, but the ratio of the middle part was not different. The ratio of hind part related to the reference carcass was largest in progeny of PW and least in LB and CL groups (P < 0.05). It was concluded that the production of growing rabbits was affected by the adult BW of their sires, but the carcass traits were influenced by their own adult BW and by the CT-based selection.