No abstract

Contemporary farming and competitive market conditions are forcing nutritionists and physiologists to seek unconventional ways to upgrade rabbits' performance. Among these, feed additives such as antibiotics, probiotics, prebiotics, and immune modulators might be a good alternative to increase weight gain, improve feed efficiency, superior physiological functions of the body, and boost immune responses.Chitosan is one of the natural feed additives. It is derived from chitin, a polysaccharide formed by N-acetyl-D glucosamine units found in insects, marine diatoms, algae, fungi, and crustacea, through deacetylation, demineralization deproteinization, and decolouration (Synowiecki & Al-Khateeb, 2003;Abd El-Hack et al., 2020Abd El-Aziz et al., 2022). Previous studies have shown that chitosan as a dietary supplement in animal feed improved the digestive system performance by absorbing accumulated toxins and treating chronic constipation and gastrointestinal ulcers. In addition, it reduced the absorption of cholesterol from the diet. Therefore, in the future, chitosan may have wider uses, such as a feed additive, to improve the productive and reproductive performance of

This experiment was designed to compare the productive performance, reproductive efficiency, physiological reactions and behavioral traits in males and females of two breeds of rabbits, Baladi Red (BR) and New Zealand White (NZW) rabbit breeds. Fifty two mature males and females rabbits were used in this experiment. Twenty six from each breed were used (6 males and 20 females). At the bigining of the experiment, age of animales averaged 4-5 months and their weight averaged 2.20-2.50 Kg for each breeds. Results of this study indicated that, there were significant differences between both breeds and sexes on most studied traits. Females had (P≤0.05) superior physiological body reactions and lower hematological parameters than those recorded for males, irrespective of breed factor. Howeber, no significant differences were found between breeds on physiological body reactions and hematological parameters, irrespective of sex of breed. Also, the results showed that, NZW rabbit bucks had significantly (P≤0.05) higher libido, whole ejaculate volume, dead spermatozoa, and insignificant higher sperm concentration/ml than those obtained in BR bucks breed. In contrast, BR rabbit bucks had (P≤0.05) higher semen pH, net ejaculate volume and initial motility, and had insignificant higher sperm concentration/ejaculate than those obtained in NZW bucks breed. Also, NZW rabbit does had significantly (P≤0.05) higher receptivity percent, litter size at weaning, milk yield and walking behavior percent, and had insignificant higher vulva color score, number of parities and litter size at birth than those recorded in BR breed. Contrary, BR rabbit does had (P≤0.05) higher, body weight after one year, kindling intervals, average kit weight at weaning, sitting behavior percent, and insignificant higher conception rate than those obtained in NZW rabbit does breed. Moreover, the results showed that, NZW rabbit breed had significantly (P≤0.05) lower mortality rate of the youngs than those recorded in BR breed. In relation to adult animals, BR was lower mortality rate than NZW breed. Moreover, the results showed that there was positive correlation between conception rate and most semen characteristics, In contrast there were negative correlations between mortality rate of the young and both female behavioral activities and milk yield. It is concluded that, libido and semen characteristics in BR bucks seems to be better than those recorded by the WNZ bucks. However, productive and reproductive efficiency in NZW does appears to be higher than those obtained from BR breed, under the same managerial conditions.

This study aimed to determine the effect of dietary chitosan supplementation on the productive and reproductive performance of New Zealand White (NZW) rabbits. Forty healthy weaned female rabbits were randomly distributed into four experimental groups (10 females per group) and fed ad libitum for six months. A basal diet without chitosan supplementation was used as a control. The other three experimental groups were fed a basal diet plus 0.2, 0.4, or 0.6 g chitosan/kg diet. After eight weeks, three females from each group were sacrificed for morphological observation of ovarian tissues. The remaining animals were used for reproductive studies by a maximum of three parities. Morphological observation of ovaries demonstrated that females fed a diet containing 0.2 g/kg chitosan had increased ovarian diameter and elevated the number of mature follicles compared with the control and the other experimental groups. Receptivity, conception rate, and kindling interval were significantly (P˂0.05) higher in females fed diets containing 0.2 and 0.4 g/kg chitosan compared to the other groups. Moreover, there was a trend toward a higher average milk yield throughout the lactating period in females fed a diet containing 0.2 g/kg chitosan (P=0.904). Diets containing up to 0.4 g/kg chitosan were positively correlated with increased receptivity rate and several parties. However, diets containing up to 0.4 g/kg chitosan were negatively correlated with decreased receptivity time, kindling interval, litter size at weaning, mortality rate at weaning, bunny weight at weaning, and milk yield. The present study’s findings indicate that diets containing 0.2 g/kg chitosan improved reproductive efficiency in female NZW rabbits.

Natural estrus induction methods were used in non receptive female rabbits for mating. Methods used were litter separation in the suckling females or presence of a female near buck cage in the non-suckling females of two differnt breeds, Baladi Red (BR) and New Zealand White (NZW). Treatments showed pronounced improvement in both breeds in terms of receptivity to males and conception rate. The NZW rabbits doe showed improvment in receptivity up to 68% in non-suckling and 73% in suckling females, while the percentages in Baladi rabbits were 72% and 79% in non-suckling and suckling ones, respectively. In addition, natrual methods tended to enhance conception rate in NZW rabbits to 74% in non-suckling and 56% in suckling females, while the corrseponding values of Baladi does were 71% and 55%, respectively. Significant decrease was observed in prolactin hormone level in response to litter separation from 42 to 6 ng/ml in NZW and from 15 to 2 ng/ml for Baladi does. However, progesterone was increased from 0.9 to 2.2 ng/ml in litter separation method and from 1.5 to 11.5 ng/ml in presence beside male cage in NZW rabbits. In Baladi does, values of progesterone hormone were increased from 0.8 to 6.7 ng/ml in litter separation and from 3.8 to 12.1 ng/ml in presence beside male cage. Estrogen levels of NZW does showed insignificant increase after litter separation and significant increase after presence beside male cage (48 to 63 pg/ml). In addition, Baladi rabbits had insignificant increase after litter separation. However, significant increase in estrogen values (from 47 to 56 pg/ml) after treatment were observed by presence beside male cage. Generally, the natural methods used to induce estrus in NZW and Baladi rabbits were successful and applicable. They can be widely used in rabbit farms instead of hormonal methods.