No abstract

The aim of this study was to evaluate the effects of freezing diluents supplemented in three potential amines/amino acids, namely, antioxidant cysteamine (2-aminoethanethiol [ AET ]), ergothioneine ( ERG ), and serine ( SER ), in optimization of chicken sperm cryopreservation. The semen of 36 Pradu Hang Dum males, selected based on their motility vigor score, was frozen by a simple freezing method using nitrogen vapors and dimethylformamide ( DMF ). In a first experiment, a wide range of AET, ERG, and SER doses were tested. Semen quality was evaluated after incubation at 5°C or after cryopreservation in straws in the Blumberger Hahnen Sperma Verdünner ( BHSV ) diluent + DMF (6% v/v) with or without AET, ERG, or SER. The best targeted doses of AET, ERG, or SER were then selected for experiment 2 that was focused on cryopreserved semen. Frozen-thawed sperm quality was evaluated by different in vitro tests and by evaluation of fertility. Objective motility parameters were evaluated by computer-assisted sperm analysis. Membrane integrity, acrosome integrity, and mitochondria function were evaluated using appropriate dyes and flow cytometry. Lipid peroxide production was assessed by the thiobarbituric acid test (malondialdehyde production). Fertility obtained with frozen-thawed semen supplemented or not in AET, ERG, or SER was evaluated after artificial insemination of laying hens. ERG and AET decreased sperm lipid peroxidation and decreased fertility, even at low doses. The presence of 4 mmol of SER significantly decreased lipid peroxidation, increased the frozen-thawed sperm quality, and increased fertility after sperm cryopreservation (90% vs. control 84%, P < 0.05). In a third experiment, the use of 1 mmol of sucrose (the best result of our previous study) added to 4 mmol of SER-supplemented extender was tested. This addition allowed to the highest levels of fertility (93%). In conclusion, the addition of 4 mmol of SER in semen cryopreservation diluents decreases peroxidation and improves the efficiency of the process.

No abstract

Chicken semen conservation is an important tool for programs of genetic diversity management and of endangered breeds’ conservation. However, the method still needs to be improved in order to be applied in a wide variety of environments and breeds. Our objective was to compare the effects of 2 external cryoprotectants saccharides (sucrose and raffinose) on the sperm freezability of a Thai local breed, Pradu Hang Dum, in which semen was frozen with a simple freezing method using nitrogen vapors and dimethyl formamide (DMF). Thirty-six males were selected on their motility vigor score for the experiments. In a first experiment, a large range of sucrose and raffinose doses were tested. Semen quality was evaluated after incubation at 5°C or after cryopreservation in straws in the saline Blumberger Hahnen Sperma Verdünner diluent + DMF (6% v/v) with or without sucrose/raffinose. The best targeted doses of sucrose and raffinose were then kept for experiment 2 that was focused on cryopreserved semen. In this experiment, semen quality was measured on frozen-thawed sperm: different objective motility data evaluated by computer-assisted sperm analysis (CASA), membrane integrity, acrosome integrity, mitochondria function evaluated using flow cytometry, lipid peroxide production assessed by the thiobarbituric acid test. Fertility obtained with frozen-thawed semen supplemented or not with sucrose or raffinose was also evaluated after artificial insemination of laying hens. The presence of sucrose at the osmotically inactive dose 1 mmol significantly increased the vigor motility, membrane integrity, acrosome integrity, and mitochondrial functions of frozen-thawed sperm ( P < 0.05), and showed the highest levels of fertility after sperm cryopreservation (91% vs. control 86%, P < 0.001). Raffinose showed negative effects on in vitro semen quality from 1 to 100 mmol. Fertility was also negatively ( P < 0.001) affected by raffinose (fertility rate 66 to 70%). We thus showed in the present study the high success of a simple chicken sperm cryopreservation method with an external cryoprotectant easily available and cheap, the sucrose, used at an osmotically inactive low concentration.

No abstract

Bovine leukocyte antigen DRB3 alleles from Holstein x Zebu crossbred dairy cows (n = 409) were analyzed using the PCR-RFLP technique. Exon II of DRB3 was amplified using locus-specific primers (HLO30/HLO32), followed by digestion with 3 restriction enzymes (RsaI, BstyI, and HaeIII). Forty alleles were found with frequency ranging from 0.005 to 0.139. The most frequently detected alleles of Holstein x Zebu were DRB3*16, *51, *23, *11, *8, and *1, accounting for 61.12% of the alleles in the population. Detection of candidate alleles for clinical mastitis occurrence was performed by logistic regression. It was found that percentage of Holstein fraction in crossbred cows had a nonsignificant effect (P > 0.05). However, parity had a significant effect on mastitis occurrence. In addition, DRB3*1 and *52 were the most associated with the occurrence of clinical mastitis, whereas *15, *51, and *22 were associated with resistance in crossbred populations. This is the first report of association of DRB3*15 and *51 with mastitis resistance. The association was validated by examining the candidate alleles in another commercial population. Highly susceptible (n = 43) and resistant (n = 42) groups of Holstein x Zebu cows were investigated. The result confirmed that DRB3*1 and *52 could be considered as susceptibility alleles, whereas *15, *51, and *22 could be considered as resistant alleles in Holstein x Zebu raised under tropical conditions. In addition, allele effects on 305-d milk production were estimated by BLUP. It was shown that most alleles associated with high clinical mastitis occurrence were related to increased milk yield. This study revealed that allele DRB3*10 had the greatest effect on increasing milk yield with moderate resistance to clinical mastitis, which could be used as a potential marker for selection in dairy genetic evaluation.

The purpose of this study was to examine sperm quality after cryopreservation of ejaculates collected as a bulk sample, which is routinely part of semen collection, and to compare this quality with the sperm-rich fraction in boars. Ejaculates were collected as sperm-rich fractions (SRF) and bulk samples (BE) using a gloved-hand technique. Fresh semen quality in terms of semen volume, sperm concentration, total sperm motility and pH were conventionally evaluated. Then, semen was cryopreserved using the liquid nitrogen vapour method. The post-thaw sperm quality was evaluated by assessing sperm motility, live sperm with normal apical ridge and high mitochondrial energy status, lipid peroxidation was evaluated using CASA and fluorescent multiple staining and MDA levels were determined using a spectrophotometer, respectively. In terms of fresh semen quality, sperm motility in fresh semen did not differ significantly between the two groups. The treatment with the greater mean volume (BE; P &lt; 0.05) had a lower mean sperm concentration (P &lt; 0.05); meanwhile, the mean ejaculate pH collected as BE was more basic compared with SRF (P &lt; 0.05). However, there were no significant post-thaw quality changes between sperm-rich fractions and bulk samples of semen. In conclusion, ejaculates can be collected as bulk samples without the need to classify fractions for boar semen cryopreservation.

Relatively few studies have been reported regarding the reproductive physiology of female Thai native cattle. Therefore, the objective of the present study was to evaluate the follicular dynamics and concentrations of follicle stimulating hormone (FSH), estradiol (E2) and progesterone (P4) during the estrous cycle in Thai native heifers (TNH) and to compare obtained results with those of European and Indian cattle breeds previously reported. For the detection of estrus, ovaries of all 20 heifers were examined twice daily (12 h intervals) by ultrasonography for three consecutive estrous cycles. From data of 60 estrous cycles (n = 60 estrous cycles from 20 heifers), it was found that 14 (70%) and 6 heifers (30%) had two (42 estrous cycles collected from 14 heifers) and three follicular waves (18 estrous cycles collected from 6 heifers), respectively. The days when estrus was detected, interovulatory intervals, life-spans of corpus lutea (CL), and days for growing and regression of CLs were shorter in the two follicular waves than those in the three follicular waves (P < 0.05). In both two and thre follicular waves, larger maximum diameters and higher growth rates of the dominant follicle (DF) in an ovulatory wave were observed than those of the preceding waves without ovulation (P < 0.05). There was a progressive increase in follicular size and FSH and E2 production during follicular growth in each follicular wave. In addition, the FSH and E2 peak concentrations during the ovulatory wave were higher than those of the anovulation waves (P < 0.05). Moreover, although the ovarian follicular dynamic patterns in Thai native heifers were similar to those previously reported for European and Indian cattle breeds, the diameter of the largest preovulatory follicle (OF), subordinate follicles (SF) and CLs were smaller than those in European and Indian cattle breeds. In conclusion, when compared with European and some breeds of Indian cattle, the length of interovulatory intervals was shorter, and the sizes of dominant SF and CLs were smaller in Thai native heifers.