Physiological, Reproductive and Productive Performance of Rabbit Doesas Influenced by N-Acetylcysteine Administration

Abstract

The present study was carried out in Rabbit Research Unit at Sakha Research Station located in Kafr El-Shiekh governorate, Egypt to assess the impact of N-acetylecysteine (NAC) administration on the physiological, reproductive and productive performance of rabbit does. A total number of 21 pregnant, healthy, primiparous New Zealand White (NZW) rabbit does aged between 5-6 months with an average initial body weight (BW) of 3052 g were used. They were divided into three equal groups. The first group (G1) was served as control group without any administration. The second and third groups (G2 and G3) were injected subcutaneously with 50 and 100 mg NAC / kg BW, respectively. The injection with NAC doses started on day 14 of pregnancy and continued for seven consecutive days. The experiment lasted continuously for three months. The obtained results showed that, NAC treatment reduced the oxidative stress in pregnant rabbit does, G2 and G3 had the highest values of GST and the lowest values of both MDA and H 2 O 2 in comparison with those of G1.Total protein, albumin, globulin and A/G ratio did not significantly affected by NAC injection and tended to increase with pregnancy progress. In contrast, level of triglycerides decreased (P<0.05) in G2 and G3 than that of G1 and declined with progress of gestation till kindling. Treated groups decreased their blood urea nitrogen (BUN) values and increased their creatinine (CR) levels than those of G1. With progress of pregnancy, levels of BUN tended to decrease and CR levels tented to increase. Both transaminase enzymes (AST and ALT) activities decreased by NAC treatment and by pregnancy progress, particularly in G3. The changes in live BW of does in the three groups across the experimental period were insignificant. NAC injection achieved weaning day, G2 and G3 had heavier kits' weight than those in G1 by 26 and 20 %, respectively. Litter size increased obviously due to NAC treatment by 19 to 35 % in G2 and by 5.5 to 23.1 % in G3 than that in G1 during the all experimental days. Mortality rate reduced by NAC injection being the lowest in G2 (4.7 %) followed by G3 (11.2%) and the highest in G1 (23.6 %). Total milk yield was increased significantly in G3 and insignificantly in G2 compared to that of G1 by 17.5 and 4.5 %,respectively. The high dose was more effective in promoting milk production. The effect of NAC treatment on all milk components was insignificant, except milk lactose. From the first wk to the last wk, milk composition (%) of milk protein, milk lactose, milk total solids and milk solids not fats increased (P<0.05) whereas milk fat decreased. In conclusion, this study proved not only the effectiveness, but also the safety of NAC application and its capability to improve rabbit's performance particularly with high dose (100 mg/kg BW). Further studies are urgently needed to confirm our findings.

Hormonal Changes in Relation to Productivity of Pregnant Rabbit Does.

“…In the present study the LS at weaning was 4.64, which was lower than that recorded at birth, and the average of BW increased eight folds higher than that at birth and reached to 2621g (Table 3). This is agreeing with Ashour et al (2018) who found that LS and LW were 4.33 and 2261g, respectively. Furthermore, there was a positive relationship (0.03, 0.13 and 0.19; P<0.05) between LS and P4 (P4 has a role in helping the fetus in implantation, as mentioned previously), E2 and PRL, respectively.…”

“…The PRL hormones as described previously, increased at late pregnancy (stimulated by rising level of E2) and the expression of PRL receptors mRNA is increasing about 4-10 fold between late pregnancy and the day of kindling, because its importance for lactogenesis 2 (Neville et al, 2002). Litter size and weight: At birth, the average of litter size (LS) was 6.33, this is closely to those reported by Kelden et al (2017) and Ashour et al (2018) who found that LS at birth was 6.8 and 5.67 in rabbit pups. The average of pup's birth weight was 325.56 g, which is mainly associated with their LS.…”

“…Milk production: The rabbit does lactate for four consecutive weeks and the average of total milk yield (TMY) was 129.94 g/d. This is in harmony with that of Ashour et al (2018). During the weeks of lactation, rabbits produced 91.66 g/d in the first week ( Figure 3).…”

“…In developing countries, rabbit production may play an important role in surmounting meat shortage especially that, rabbit's meat is characterized by highly nutritive value including low fat, cholesterol and increased protein level (Wahab et al, 2016). Despite of this distinctiveness, rabbit farming in Egypt is facing many constraints such as diseases, heat stress and poor feed quality (Ashour et al, 2018). Therefore, to improve this valuable industry, rabbit breeders need to understand their reproductive biology that considered fundamental step in rabbit farming success (Ashour et al, 2018).…”

“…Despite of this distinctiveness, rabbit farming in Egypt is facing many constraints such as diseases, heat stress and poor feed quality (Ashour et al, 2018). Therefore, to improve this valuable industry, rabbit breeders need to understand their reproductive biology that considered fundamental step in rabbit farming success (Ashour et al, 2018).…”