R.P. Moudgal

Effects of hemicastration and castration on foam production and its relationship with fertility in male Japanese quail

Healthy heavy body weight strain of adult male Japanese quail (Coturnix coturnix Japonica) of the same age were used in this study to observe the effect of hemicastration and castration on the frequency of foam discharges from cloacal gland and other related parameters. The quails were housed in individual cages and divided into four groups: control (intact birds), sham-operated control (intact birds with incision), hemicastrated, and castrated groups of birds. Hemicastration and castration were carried out surgically at 10 and 13 weeks of age, respectively. Subsequently, 3 weeks after castration birds were examined for different parameters. Hemicastration caused a significant (P < 0.05) drop in the foam discharge frequency, weight of the foam, and the level of testosterone in the plasma, whereas in castrated group these variables were observed nil or negligible as compared to both of the controls. A suppressive effect of hemicastration was also noticed on the body weight, area of the cloacal gland, as well as percent fertility. Castration induced the drastic regression of the cloacal gland and a significant reduction (P < 0.05) of the body weight was also noted as compared to other groups. Frequencies of foam discharges were twice the number in daytime (06:00-18:00 h) than night, irrespective of the groups. In another study, the effect of characteristics of foam or foam glands on fertility was examined in 77 male birds paired with females. Several characteristics of foam and foam glands were examined for infertility, such as light yellow foam, dark yellow foam, smaller area of foam gland (below 225 mm2), hardness of foam gland and certain unknown factors that contributed 0.23, 0.68, 5.23, 2.27 and 3.64% infertility, respectively. An overall 12.1% birds were found to be infertile. This data indicated that smaller sizes of foam glands might reflect the poorest fertilizing ability of the male birds. From this study, it may be concluded that the cloacal gland may be considered as an external indicator of testicular function of the birds. Characteristics of the cloacal gland or foam or both may be used as a simple and effective tool to predict the fertilizing ability of an individual male in view of the very small semen ejaculate that is very difficult to collect and evaluate for fertility.

Involvement of corticosterone in food intake, food passage time and in vivo uptake of nutrients in the chicken (Gallus domesticus)

To evaluate the effect of corticosterone on nutrient transport, 10-week-old male chickens were grouped in 4 categories and treated as follows: sham-operated, adrenalectomised, corticosterone (4 mg/kg injected subcutaneously for 5 d) in both sham-operated and adrenalectomised. The food intake, food passage time and uptake of calcium, phosphorus and glucose were determined by standard procedures. Corticosterone administration to both sham-operated and adrenalectomised groups stimulated significantly higher food intake, delayed food passage time and increased uptake of calcium, phosphorus and glucose, as compared to sham-operated control and adrenalectomised groups. Corticosterone administration increased absorption of these nutrients significantly more in the adrenalectomised group than in the sham-operated controls. Corticosterone also significantly elevated the plasma concentrations of these nutrients. The responses to the hormone were significantly greater in adrenalectomised birds. It is concluded that corticosterone increases food intake and retention and the absorption of calcium, phosphorus and glucose in the alimentary tract.

Protective effects of melatonin in reduction of oxidative damage and immunosuppression induced by aflatoxin B1-contaminated diets in young chicks

In the present study, the ability of aflatoxin B1 (AFB1) to induce endogenous oxidative damages and the possible ameliorating effects of dietary melatonin (MEL) were investigated. Newly hatched broiler chicks (n = 240) were fed aflatoxin‐contaminated diets (0.5 or 1 mg kg−1 diet) with or without MEL (40 mg kg−1 bw) supplementation in diet for 40 days. AFB1 resulted in a significant increase in lipid peroxidation (LPO) in the liver and erythrocytes accompanied with suppression of superoxide dismutase (SOD) and catalase (CAT) enzyme activities of erythrocytes. It also caused a significant reduction in levels of serum proteins and marked elevation in activities of serum transaminases. AFB1 treatment also decreased both humoral and cell‐mediated immune responses in growing chicks. Simultaneous administration of MEL with AFB1 resulted in an obvious improvement in all the tested parameters. Long‐term rather than short‐term administration of MEL was more effective in rendering protection against AFB1‐induced toxicity.

Cloacal gland foam enhances motility and disaggregation of spermatozoa in Japanese quail (Coturnix japonica).

The adult male Japanese quail produces white foam from the cloacal gland, which is transferred to the female proctodeum during natural mating. The physiological role of foam on quail spermatozoa is still unclear. Therefore, attempts have been made to understand the effect of cloacal foam on motility and metabolism of quail spermatozoa. The profile of various biochemical constitutes in the foam extract was investigated. The addition of foam extract to neat semen completely disaggregated the clumps of spermatozoa leading to vigorous motility. The metabolic rate (MBRT) of the spermatozoa was significantly increased with the addition of foam extract. The foam extract was sub fractionated into seven different fractions by using the molecular cut off devices. Among all the seven sub-fractions from the foam extract, the addition of < 1 KDa sub-fraction contained lactate and has enhanced sperm motility and metabolism. Another fraction (3-10 KDa) has non-protein and non-heparin components which completely disaggregated the clumped quail spermatozoa. However, the remaining fractions did not show any effect on quail spermatozoa. It can be concluded from the present investigation that the lactate present in foam might be a fuel for sperm metabolism and motility. Furthermore, low molecular weight (3-10 KDa) components in the foam may responsible for sperm disaggregation.

Characterization of lactate dehydrogenase enzyme in seminal plasma of Japanese quail (Coturnix coturnix japonica)

Lactate dehydrogenase enzyme present in quail seminal plasma has been characterized. Polyacrylamide gel electrophoresis and subsequently with LDH specific staining of seminal plasma revealed a single isozyme in quail semen. Studies on substrate inhibition, pH for optimum activity and inhibitor (urea) indicated the isozyme present in the quail semen has catalytic properties like LDH-1 viz. H-type. Furthermore, unlike other mammalian species, electrophoretic and kinetic investigations did not support the existence of semen specific LDH-X isozyme in quail semen. The effect of exogenous lactate and pyruvate on sperm metabolic activity was also studied. The addition of 1 mM lactate or pyruvate to quail semen increased sperm metabolic activity. Our results suggested that both pyruvate and lactate could be used by quail spermatozoa to maintain their basic functions. Since the H-type isozyme is important for conversion of lactate to pyruvate under anaerobic conditions it was postulated that exogenous lactate being converted into pyruvate via LDH present in semen may be used by sperm mitochondria to generate ATP. During conversion of lactate to pyruvate NADH is being generated that may be useful for maintaining sperm mitochondrial membrane potential.

Ovarian morphology and internal vis-à-vis non internal laying in relation to triacylglycerol, hormones and their receptors concentration around the age of sexual maturity in broiler breeder hens

1. Ovarian morphology, serum hormone concentrations of 17-β-estradiol, progesterone, testosterone, tri-iodothyronine (T3), thyroxine (T4) and triacylglycerol (TAG) were investigated at 23 and 26 weeks of age in broiler breeder hens provided with ad libitum access to feed. Progesterone, oestrogen-β, thyroid-α and -β receptor mRNAs were also quantified in the infundibulum at the same ages. 2. A large variation in the ovarian morphology was observed at 23 weeks of age including hens with undeveloped ovaries, non-laying hens with post ovulatory follicles (POF) and a predominance of non-laying hens without a POF. 3. Serum concentrations of triglyceride, 17-β-estradiol and progesterone at 23 weeks of age were lower in hens with an undeveloped ovary compared with other groups of hens, whereas testosterone, triiodothyronine and thyroxin were higher. 4. At 26 weeks of age, the average number of hierarchical yellow follicles in normal layers was 7.64 ± 0·41 whereas in internal layers, the follicular numbers were significantly greater at 8.66 ± 0·53. The higher follicular numbers in internal layers were associated with higher serum triglyceride and progesterone concentrations. 5. Oestrogen receptor-β and thyroid receptor-β mRNA was up regulated in the infundibulum of internal layers compared with normal laying hens at 26 weeks of age.

Influence of chicken native breeds on some physical and biochemical characteristics and short-term storage of semen

1. The major objective of this study was to examine the influence of 24-h storage of semen at low temperature on semen characteristics and fertilising ability of spermatozoa in two native breeds (Kadaknath – KN, Aseel Peela – AP) and White Leghorn (WL) chicken. 2. Various physical and biochemical properties of freshly ejaculated semen of KN and AP were investigated. Fertility was examined in freshly-ejaculated as well as 24-h-stored (3°C) semen diluted (1:3) with Beltsville Poultry Semen Extender. 3. No significant difference was observed in sperm motility among the different breeds whereas live counts were higher in WL than the native breeds. Body weight, semen volume and sperm concentration were highest in AP, followed by KN and WL. A similar trend was observed in the percentage of dead and morphologically-abnormal spermatozoa. 4. The activity of acid and alkaline phosphatase in seminal plasma were higher in WL than KN, whereas the opposite trend was recorded for glutamic oxaloacetic and pyruvic transaminases. The cholesterol content of semen was highest in AP, followed by KN and WL. Cholesterol was much lower in seminal plasma compared with whole semen but there were no differences between breeds. Mean values of the methylene blue reduction time test were higher in WL than in the native breeds. 5. Fertility and hatchability, using freshly-diluted semen, were poorer in the native breeds than in WL. The pattern of fertility deteriorated further, especially in native fowls, when the birds were inseminated with 24-h-stored semen. 6. In conclusion, variation in physical and biochemical characteristics of semen in native breeds compared to WL correlated with poor fertility after short-term storage of semen.

Effects of cold shock treatment on angiotensin-converting enzyme activity and on semen characteristics in roosters and bulls

Angiotensin-converting enzyme (ACE) activity has been determined in the semen of certain avian and mammalian species as well as its release during cold shock. The maximum and minimum levels of this enzyme were found in mammalian spermatozoa and in seminal plasma, respectively. It was found that ACE activity in mammalian spermatozoa was more pronounced than in the seminal plasma, whereas in the avian species a revers pattern was observed. However, there were no significant differences in ACE activity in spermatozoa and seminal plasma between layer and broiler strains of avian species. By contrast, ACE activity in the spermatozoa and seminal plasma of buffalo bulls was significantly higher (P/ 0.01) than in cattle bulls. Cold shock did not significantly alter semen characteristics in avian species, while a significant (P/ 0.01) decrease in sperm live counts and motility as well as a corresponding increase in morphological abnormalities were observed in the spermatozoa of cattle and buffalo bulls due to cold shock.

Variation in angiotensin-converting enzyme activity in the testes of prepubertal, pubertal and adult cockerels.

The variation in the level of angiotensin-converting enzyme in the testes of prepubertal, pubertal and adult cockerels were investigated. Maximum levels of angiotensin-converting enzyme were observed at 8 wk of age, followed by a progressive decrease (P/0.01) until 14 wk of age. After this stage, however, a rapid growth rate of the testes and comb was noted. The concentration of angiotensin-converting enzyme in pubertal and adult birds remained at a significantly lower level than in the prepubertal birds. The level of activity of this enzyme was significantly but negatively correlated with age and with the weights of the testes and comb. The high level of this enzyme found in prepubertal cockerels suggests it may be more highly involved in the early rather than later stages of spermatogenesis.

The influence of prepubertal partial sinistral ovariectomy on the subsequent reproductive function of domestic hens (Gallus domesticus ).

Each of 20 White Leghorn hens of 13 to 14 weeks were subjected to partial sinistral ovariectomy and sham-operations. In half of the hens from each group, the percentage of egg production and clutch size were noted until 50 weeks of age. The growing pattern of normal ovarian follicles was also recorded at 26 weeks of age in a rest half ofthe hens in the two groups. The percentage of egg production and the mean and variance of clutch size did not differ significantly (P / 0.05) between the partially ovariectomized and sham-operated groups. The growing yellow follicles (>8 mm) in the rapidly developing phase in these two groups did not vary, although the smaller follicles (4 to 8 mm in diameter) remained significantly (P / 0.01) more in the shamoperated control group than in the partially ovariectomized group. This observation indicates that smaller follicles (4 to 8 mm) developed in the larger (>8 mm) follicles more efficiently in partially ovariectomized hens than in the sham-operated (control) hens. In a second experiment, one group of hens had all the yellow follicles (>8 mm) removed, while a second group of hens was left untreated. On the 3rd and 6th day post treatment, the hens were examined for the presence of ovarian follicles. No significant (P / 0.05) difference in the growing pattern of subsequent follicles (2 to 4 or 4 to 8 mm) was detected due to treatment. These data demonstrate that the mechanisms that regulate follicular growth and atresia are adjust to maintain normal ovulation following partial ovariectomy.