No abstract

The current study was performed to evaluate the effects of the dietary inclusion of extra virgin olive oil (EVOO), betaine (BET), lemongrass essential oil (LGEO), gallic acid (GA), vitamin C (VC) and vitamin E (VE) on different body temperature traits and stress hormone and glucose levels in heat-stressed growing rabbits. Rabbits were fed diets with no supplementation (control group) or supplemented with 15 g of EVOO, 400 mg of LGEO, 500 mg of GA, 1000 mg of BET, 500 mg of VC, or 200 mg of VE per kg of diet. All tested feed additives, especially EVOO, had a lowering effect on various rabbit temperature traits. Both triiodothyronine (T3) and tetraiodothyronine/thyroxine (T4) were increased (p<0.05) by the addition of BET, VC, EVOO, and VE. With the exception of the VC group, all dietary groups showed no significant changes in the insulin level compared to the control group level. In contrast, the cortisol and glucose levels were diminished (p<0.05) in all treated groups compared to the control levels. The results suggested that all tested supplementations had positive ameliorating effects on growing rabbits under a severe heat load in terms of lowered body temperatures and a favourable stress hormone balance, with the most favourable results found in the EVOO, VC, and BET supplementation groups.

This study explored the effects of supplemental dietary extra virgin olive oil (EVOO), gallic acid (GA), or lemongrass essential oil (LGEO) on growth performance, nutrient digestibility, carcass traits, lipid peroxidation, hematological, and antioxidative status in growing rabbits under heat stress conditions. A total of 48 male growing New Zealand White rabbits were randomly divided into four equal groups, which received a basal diet without any supplementation or supplemented with 15 g EVOO, 500 mg GA, or 400 mg LGEO/kg of diet, for eight consecutive weeks. Results revealed that the overall mean of temperature humidity index was 84.67 ± 0.35, reflecting a state of severe heat stress. Moreover, dietary supplementation with EVOO, GA, or LGEO significantly increased live body weight and daily body weight gain but decreased both feed conversion ratio and daily water consumption. Additionally, a significant increase in both organic matter and crude protein digestibility besides a remarkable elevation in the nutritive values of digestible crude protein, total digestible nutrients, and digestible energy, as well as an increase in the numbers of WBCs, lymphocytes, and heterophils was significant in EVOO-supplemented rabbits. Supplementation with EVOO, GA, or LGEO in the heat-stressed growing rabbit's diet enhanced catalase activity and reduced glutathione content, whereas EVOO-treated rabbits had the highest values. Also, malondialdehyde activity was reduced in response to all tested additives. In conclusion, these findings suggested that addition of EVOO, GA, or LGEO in growing rabbit's diet could be used effectively to alleviate negative impacts of heat stress load on performance, nutrient digestibility, oxidative status, and hemato-biochemical features. Furthermore, among these additives, EVOO achieved the best effects.

Abstract. The aim of the study was to carry out crossing of the local breeds with a known prolific breed with the hope to be a beginning to develop improved synthetic lines under the sub-tropical conditions. In the present study, the data represented 4 genotypes: 2 pure Egyptian local fat-tailed breeds [Ossimi (O) and Rahmani (R)], one back-cross [1/4 Finnish Landrace (F) 3/4 O] and one 3-breed-cross [1/4 F 1/4 O 1/2 R]. The lambs resulted from two accelerated systems: 3 lambings/2 years and 2 lambings/1 year. The results showed that in 3 lambings/2 years and 2 lambings/1 year systems, the crossbred lambs were significantly (P<0.01 or 0.05) higher in most of the growth traits, carcass characteristics and weight of ewe lambs at first mating, and were significantly (P<0.01) lower in percentages of the tail and bone and age of ewe lambs at first mating than in their maternal (local) breeds. Spring born lambs were significantly (P<0.01 or 0.05) higher than those born in the other seasons of the year in body weights at 16 and 24 weeks of age and daily gain weight during 0–<8 weeks in 3 lambings/2 years system, and in daily gain weight during the period 8–<16 weeks of age in 2 lambings/1 year system. When using some indices based on combining a number of economic traits of the study (including slaughter weight, feed efficiency, dressing percentage, percentage of lean in the carcass, conception rate, lambing rate and average litter size) to compare the crossbreds with the local ones, the obtained values were not in favour of the crossbreds, which may throw some shadows on feasibility of applying crossing of the Egyptian local sheep with the Finnsheep. Comparison between the two mating systems showed that the 3 matings/2 years surpassed the 2 matings/1 year system in all the indices developed. When calculating the productive efficiency per one year by combining the traits: survivals ratio – that equals: 1 − (mortality rate at 8 weeks) – and frequency of lambing per one year, the values were 15.0 and 13.2 % in the two systems, respectively, confirming the previous results.

No abstract