Experimental results in the field of nutrition and carcass traits of rabbits at Kaposvàr University between 2008 and 2012

In this paper we summarize the results of experiment carried out during the last five years. Exp. 1. The aim of the experiment was to study the influence of feeding medicated or non-medicated diets followed by a feed restriction after weaning on the productive and carcass traits of growing rabbits. Half of the rabbits was fed non-medicated (NOMED), while the other half was fed medicated diet (MED) between 4 and 9 weeks of age then they consumed non-medicated diet afterwards. Within both diet groups, half of the rabbits was fed ad libitum (ADLIB), while the other half restricted (RESTR). In the latter group rabbits were allowed to consume for 9, 10, 12 or 14 hours between 4-5, 5-6, 6-7 or 7-8 weeks of age, respectively, then, they were fed ad libitum afterwards. The feed intake was 26.7, 18.3 (P<0.001) and 5.3% (P=0.059) lower in the RESTR group at the ages of 4-5, 5-6 and 6-7 weeks, respectively. After 7 weeks of age no difference was found between groups. Body weight gain of RESTR rabbits was 20.9 (P<0.001) and 8.5% (P=0.039) lower at the ages of 4-5 and 5-6 weeks, resp., while between 6 and 8 weeks of age it slightly increased. Body weight of RESTR rabbits was 9.2% lower at 5 weeks of age compared to ADLIB group (871 vs. 959 g) but this was partly compensated at the end of the experiment (2737 vs. 2799 g, P=0.056). Feed conversion of RESTR group was better compared to ADLIB rabbits (2.57 vs. 2.64, P=0.01). No significant difference was found in the mortality (1 vs. 3.6%). Dressing out percentage (59.4 vs. 58.6%, P<0.001) and the proportion of hind part (19.2 vs. 18.8%), of hind legs (18.3 vs. 18.0%) and that of the m. Longissimus dorsi (7.1 vs. 6.8%) to the body weight were higher in ADLIB rabbits. No difference was found in the proportion of perirenal fat. Production and mortality of MED and NOMED groups were similar; however, the feed intake and the body weight gain of MED rabbits decreased during the transition from MED to NOMED diet at 9 weeks of age. Exp. 2. The objective of the study was to evaluate the effects of time of changing the breeding diet to fattening pellet on the production of does and growing rabbits. In the first group the does and their kits received breeding pellet till weaning (TT group; n=60). In the second group the breeding pellet was replaced by growing pellet at the 21st day of lactation (TN group; n=59). The rabbits were fed both pellet types ad libitum. The kits were weaned at the age of 35 days. No significant differences were observed for kindling rate, litter size and litter weight. The changing of the pellet affected the body weight of the rabbit does at the 35th day of lactation (-80g, P=0.016, TN<TT), the individual and litter weight of the kits at the 35th day of age (-326g, P=0.001; -42 g, P<0.001, TN<TT) and the condition of the does after parturition. For the growing rabbits the weight differences that were observed at weaning remained until the end of the growing period (11 weeks of age: +91g, P=0.033 in favour of TT group). No significant differences were observed for feed consumption and for feed conversion ratio. Based on the results, feeding the rabbits with breeding pellet until weaning was favourable. Exp. 3. The objective of the experiment was to analyze the production and carcass traits of growing rabbits fed by medicament free or by supplemented (with coccidiostatic, or with 3 different tannin levels) pellet. From the age of 18 days the rabbits were fed by medicament free pellet supplemented by coccidiostaticum (Cc), or by tannin (400g/100kg: T400). At weaning (35 days of age) within both groups 5 sub-groups were formed: medicament free (CO), and supplemented pellet containing coccidiostaticum (Cc), or different levels of tannin (Farmatan) (T200, T400 and T600). At weaning the body weight of the Cc rabbits was significantly higher than that of the T400 rabbits. Except for this finding the fed pellet type did not influence the growing rabbits’ production. The pellet type fed prior to weaning significantly affected the perirenal fat weight (Cc = 28.9 and T400 = 26.3 g; P<0.05). The rabbits fed by tannin supplemented pellet after weaning had a higher mid part ratio (P = 0.1). The mortality rate was low in all groups. It can be concluded that no positive effect can be expected when the rabbits are healthy and the housing conditions and the feed compositions are adequate. Exp. 4. The aim of the experiment was to analyse, how additional dietary linseed oil, vitamin E and selenium affects production and slaughter characteristics and meat quality of growing rabbits. The basal diet (A) contained 3% sunflower oil, while in the experimental feed (K) sunflower oil was changed to 3% linseed oil. The vitamin E and selenium content of the two diets was 60 vs. 260 mg/kg and 0.10 vs. 0.46 mg/kg, resp. Rabbits were fed the A diet from the age of 18 days. One group was fed with the A diet until 11 weeks of age, while the experimental groups were fed the K diets for 1, 2, 3 and 4 weeks before the slaughter (K1, K2, K3 and K4 groups). The production performance was identical in all groups. The dressing out percentage was the lowest in the K1 group (61.7%), while it was significantly higher (P<0.05) in the K2 and K3 groups (62.8 and 62.7%). The proportion of the mid part was the lowest in the K1 group and the highest in the K3 (31.3 vs. 32.0%, P<0.05). The proportion of the hind part was the highest in the K1 group (P<0.05) and the lowest in the K2, K3 and K4 groups (38.8 vs. 37.3; 37.2 and 37.1%). The proportion of the fore part and that of the perirenal fat was identical in all groups. It was concluded that additional dietary linseed oil, vitamin E and selenium has no or only a slight effect on the production and slaughter characteristics. Exp. 5. The objective of the study was to evaluate the effect of supplementation and the length of the supplementation) of the growing rabbits’ diet by Spirulina or/and Thyme on the growing rabbits’ production. At weaning the rabbits were randomly sorted to 7 groups (42 rabbits/group). Rabbits of the control group (C) received a pellet throughout the experiment (5-11 weeks of age) without any supplementation. In the other groups the pellet was completed by 5% Spirulina (S), or 3% Thyme (T) or by both (ST) for the whole (5-11 wk; groups: S-S, T-T, ST-ST), or for end of the growing period (8-11 wk; groups: C-S, C-T, C-ST). Supplementing the diet by Spirulina or/and Thyme had no effect on the rabbits’ weight gain, body weight, feed consumption, morbidity and mortality. Significant differences were only found for feed conversion ratio (8-11, 5-11 weeks) of the C-T and C-C groups to the advantage of the C-T rabbits (P<0.05). The carcass traits of different groups did not differ significantly. Based on the results the feed supplements applied separately or jointly had no substantial effect on the growing rabbits’ production and health status.