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Conjugated linoleic acid (CLA) is known for its multiple benefits including improvement of growth, increasing lean mass, and anti-carcinogenic effects. However, when used in longterm supplementations CLA does not improve semen parameters in boar and bull and reduces fertility in Japanese quails. The content of unsaturated fatty acids in dietary lipids plays a significant role in spermatogenesis owning the high proportion of unsaturated fatty acids in plasma membrane of sperms. Whether CLA plays a role in testicular tissue and epididymal fat is still unknown. Therefore, in this study we hypothesize that long-term supplementation of equal proportion of CLA isomer mix (c9,t11-CLA and t10,c12-CLA) in rabbit bucks might alter male reproductive potentials. Twelve V-Line weaned male rabbits were used in 26 weeks trial, rabbits were individually raised and randomly allocated into three dietary groups. Control group (CON) received a basal diet, a group received 0.5% CLA (CLA 0.5%), and a group received 1% CLA (CLA 1%). Rabbits were euthanized at the end of the trial and several parameters were evaluated related to growth, semen quality, and testicular and epididymal tissue histopathology and transcriptome. The long-term supplementation of CLA increased feed intake by 5% and body weight by 2-3%. CLA 1% decreased sperm progressive motility. In testicular tissue L-carnitine and α-tocopherol were decreased by CLA supplementation. In epididymal fat, CLA tended to decrease concentration of polyunsaturated fatty acids, the expression of SCD5 gene was upregulated by CLA 1% and CASP3 gene was upregulated by CLA 0.5%. Transcription of PPARG was downregulated by CLA. Feeding 1% CLA also decreased testicular epithelial thickness. Long-term supplementation

This study was carried out to improve the freezability of buck semen using two different types of cryoprotectants supplemented with melatonin as antioxidant in cold and hot temperature of breeding season. Ejaculates from four mature Egyptian baladi bucks were pooled after collection. Semen was extended with Tris-fructose-citric containing egg yolk using glycerol and dimethyl sulfoxide supplemented with two doses of melatonin (10-6 M and 10-3 M) in addition to control group. Types of motility as well as velocity, enzymatic activity and expression profile of selected genes were measured. The results revealed that the progressive motility percentage was significantly higher in samples supplemented with low dose of melatonin (10-6 M) compared to high dose (10-3 M) in glycerol (74.4 versus 64.4) and Dimethyl Sulfoxide (DMSO) based extender (35.5 versus 32.9) in cold temperature. The same trend was found in samples cryopreserved with glycerol (75.1 versus 53.5) and DMSO (32.1 versus 22) in hot temperature. The results also demonstrated that CASA parameters (VAP and VCL) were significantly increased in low compared to high melatonin dose in glycerol based extender during cold and hot temperature. The activity of total antioxidant capacity (TAC) was significantly higher in samples supplemented with low (0.49 mM/L) than high melatonin dose (0.16 mM/L) in DMSO extender. CPT2, ATP5F1A and SOD2 genes were up regulated in glycerol based extender groups in cold temperature compared to other groups of this study. On the other hand, NFE2L2 gene was upregulated in groups cryopreserved with DMSO in hot temperature compared with all other experimental groups. Therefore, it could be concluded that the glycerol based extender in cold season supplemented with low dose of melatonin improved semen quality, antioxidant defense capacity and transcriptional profile, which may maintain the post-thaw fertilizing ability of buck semen.

This study was carried out to monitor the fertilizing ability of rabbit semen frozen in the presence of melatonin as antioxidant. Semen from 10 mature Egyptian Baladi red bucks was pooled, extended with Tris-glucose-citric extender (1:1 v/v) supplemented by three concentrations of melatonin (10 -9 , 10 -6 and 10 -3 M) in addition to control, and finally cryopreserved at -196°C. After thawing, sperm kinetics, antioxidant capacity and fertility traits were evaluated. The results showed that total and progressive motility percentages were higher significantly in samples cryopreserved by melatonin (10 -6 M) as compared to control group. Curvilinear and average path sperm velocities were significantly higher in melatonin groups of 10 -9 and 10 -6 M than in the control group. Supplementation of melatonin at 10 -9 M and 10 -6 M groups decreased (P < 0.05) malondialdehyde activity when compared to the control one. In contrast, the total antioxidant capacity and catalase activity were significantly (P < 0.05) elevated at concentration of 10 -6 M melatonin as compared to the control group. In addition, transcript abundance of NFE2L2 and SOD1 genes increased in groups supplemented with melatonin compared to the control group. The fertility trial indicated that pregnancy rate, and the total and live born increased significantly (P < 0.05) in rabbit does inseminated with semen of 10 -6 M melatonin group in compared to the control samples. Conclusively, these results concluded that using melatonin with 10 -6 M level in rabbit freezing extenders could be recommended to improve semen quality and fertilizing ability of buck sperm post-thawing.

The study was carried out to find the relation between subclinical endometritis (SCE) and postpartum (pp.) ovarian resumption as well as to evaluate serum and endometrial TNF-α, IL-8 and serum CRP in buffaloes with and without SCE. Thirty-nine pluriparous buffaloes at the 3 rd (W3), 5 th (W5) and 7 th (W7) week pp. were involved in this experiment. The parity of the buffaloes ranged from 4 to 8 with an average 5.8±0.2. Subclinical endometritis was diagnosed by the percentage of polymorphonuclear cells (PMNs) in uterine cytology obtained from endometrial cytobrush at W5 and W7. The cutoff point of PMNs% in buffaloes for SCE was ≥ 6% at W5 or ≥ 4% at W7. According to PMNs%, buffaloes were divided into SCE group (n=27) and non-SCE group (n=12). Ovarian cyclicity was monitored by rectal palpation, ultrasonography and progesterone assay at W3, W5 and W7. Serum and endometrial TNF-α, IL-8 and serum CRP were estimated at W5 and W7. Buffaloes with SCE (55.6%) showed delayed ovarian activity as compared to non-SCE (16.7%) animals (P=0.036). Significant increase in serum cytokines and CRP levels were detected at W5 (P ˂0.05) and W7 (P <0.01) in SCE buffaloes as compared to non-SCE. Endometrial levels of cytokines were significantly (P ˂0.05) elevated in SCE buffaloes. Serum and endometrial cytokines showed significant positive correlation. Furthermore, levels of TNF-α, IL-8 and CRP exhibited significant positive correlation with PMNs%. In conclusion, SCE delayed postpartum ovarian cyclicity in buffaloes. Moreover, TNF-α, IL-8 and CRP assessments could be efficient tools in prediction of SCE in buffaloes.

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