Behavioural responses of cockerels to semen collection and their influence on semen characteristics

Acute Heat Stress Changes Protein Expression in the Testes of a Broiler-Type Strain of Taiwan Country Chickens

Heat stress leads to decreased fertility in roosters. This study investigated the global protein expression in response to acute heat stress in the testes of a broiler-type strain of Taiwan country chickens (TCCs). Twelve 45-week-old roosters were randomly allocated to the control group maintained at 25°C, and three groups subjected to acute heat stress at 38°C for 4 h, with 0, 2, and 6 h of recovery, respectively. Testis samples were collected for hematoxylin and eosin staining, apoptosis assay, and protein analysis. The results revealed 101 protein spots that differed significantly from the control following exposure to acute heat stress. The proteins that were differentially expressed participated mainly in protein metabolism and other metabolic processes, responses to stimuli, apoptosis, cellular organization, and spermatogenesis. Proteins that negatively regulate apoptosis were downregulated and proteins involved in autophagy and major heat shock proteins (HSP90α, HSPA5, and HSPA8) were upregulated in the testes of heat-stressed chickens. In conclusion, acute heat stress causes a change in protein expression in the testes of broiler-type B strain TCCs and may thus impair cell morphology, spermatogenesis, and apoptosis. The expression of heat shock proteins increased to attenuate the testicular injury induced by acute heat stress.

A diagnostic method for gander selection in Zi geese (Anser cygnoides L.) and Rhin geese (Anser anser L.) using massage reaction and semen quality

The objective of this study was to score reactions to artificial semen collection procedures and to develop an efficient method for gander selection in two original geese breeds. One-hundred and three Zi geese and 110 Rhin geese were used. Gander reaction scores to massage and semen quality parameters were investigated in 10 Zi and 10 Rhin ganders during a complete reproductive season. The relationships between average gander massage reaction score and semen quality were evaluated. After natural mating, egg fertility comparison between Zi ganders selected by massage reaction scores and those not subjected to selection were investigated. Ganders exhibited large variations in artificial semen collection and semen characteristics between breeds. Only 30.1% (31/103) of Zi geese and 46.3% (51/110) of Rhin geese had stable positive massage reactions with semen ejaculation (P < 0.05). Average massage reaction score, ejaculate volume, spermatozoa concentration, sperm motility and semen quality factor for single ejaculate were significantly higher in Zi than in Rhin geese. There was a high correlation between average massage reaction score and semen volume, being 0.87 for Zi geese (P < 0.05) and 0.82 for Rhin (P < 0.05), and this correlation enabled pre-selection of ganders at the beginning of the breeding season. Reproductive efficiency could be improved with massage-selected ganders in natural breeding flocks. Examination of gander massage reaction scores combined with laboratory assessment of semen quality early in the breeding season is a feasible method for predicting fertilising capability of ganders.

Annual variation in semen characteristics of pigeons (Columba livia)

The purpose of this study was to evaluate annual semen characteristics of pigeons (Columba livia). Ten selected male pigeons, aged 2 to 5 yr were housed under natural environmental conditions, and semen collection was conducted via a digital massage twice weekly throughout the year. The success rate of semen collection in a total of 920 attempts was 40% (371/920) over the whole year. The highest success rate was 69% (55/80) in March followed by 66% (53/80) in November, whereas the lowest rates were in August (13%,10/80) and September (13%, 8/60) (P < 0.01). Volume of the ejaculate averaged 11.0 +/- 0.9 microL (mean +/- SEM). The greatest volume was obtained in November (13.5 +/- 1.0 microL), whereas the least was obtained in August (7.0 +/- 1.0 microL). The average sperm motility was 72 +/- 2% of all ejaculates, of which the highest motility (82 +/- 2%) was observed in March, whereas the least motility (48 +/- 3%) was in August. Sperm viability and sperm motility were positively correlated (r = 0.91; P < 0.01). Maximum sperm concentration was 4.9 +/- 0.4 x 10(9) sperm/mL noted in March, whereas the minimum was 3.8 +/- 0.2 x 10(9) sperm/mL observed in October. Donors generally exhibited susceptible (54%) or dull submission (43%), whereas resistance to handling was rarely observed (3%). During collections, a red (47%) or pink (44%) cloacal membrane was often observed, whereas during only 9% of the collections, the cloacal membrane was pale. When the ambient temperature decreased below 15 C, semen could not be obtained (0/80). A high amount of semen (>10 microL) was obtained when the temperature ranged between 19 and 24 C. Optimal sperm motility (approximately 80%) and viability (>85%) was observed when the temperature was between 18 and 24 C. At temperatures greater than 28 C, sperm motility and viability decreased. Sperm concentration was not significantly influenced by temperature fluctuations. In summary, annual variation in semen characteristics exhibited two peaks per year with mean motility and viability reaching peak annual values in March and November. Both of these months had mean ambient temperatures between 19 and 24 C, a range associated with maximal ejaculatory volumes.