J.S. Tyagi

Effect of in ovo threonine supplementation on early growth, immunological responses and digestive enzyme activities in broiler chickens

1. The effects of injecting threonine in ovo on early growth, some immunological responses and the activity of digestive enzymes of broiler chicks were investigated. Fertile eggs were distributed into 6 groups, each of 60. These were: untreated control, sham control, 10, 20, 30 or 40 mg threonine. Threonine was dissolved in 0·5 ml sterile saline and inoculated into the yolk sac of the 14-d-old embryo through the narrow end of the egg. 2. The ratio of chick to egg weight was 1·6% higher in the group given 30 mg threonine and at 28 d of age chicks receiving threonine were 29 to 79 g heavier than untreated controls. 3. Food conversion ratio until 7 d after hatching was improved in those chicks receiving 10, 20 or 40 mg threonine but there was no significant effect on the activities of amylase, pepsin or trypsin. 4. The humoral response to sheep red blood cells was significantly greater in those groups receiving 10, 20 or 30 mg threonine supplementation than in untreated controls. 5. The response to phytohaemagglutinin-P, a measure of the cell-mediated immune response, was not affected, however. 6. It is concluded that injections of 20 to 30 mg threonine into yolk sac can improve post-hatching growth and humoral responses of broiler chicks.

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.

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.

Development of a new method for sperm RNA purification in the chicken

Currently RNA transcripts are being used as male fertility biomarker for many mammalian species, but research work on chicken is at halt because classical RNA isolation methods are not effective for chicken spermatozoa. Hence, attempts have been made to optimize RNA isolation protocol from chicken sperm by using different methods, and to confirm the presence of sperm-specific transcripts of PRM and PLCZ1. Semen samples were centrifuged at low speed for removing debris like uric acid. Further, 1mL diluted semen was gently placed over 40% PureSperm or 45%/90% Percoll, and centrifuged to remove somatic cells and immature diploid spermatocytes. RNA was isolated from sperm by using RNAzol or TRIzol reagent or RNeasy Micro kit with certain modification, and RNA quantity and quality were evaluated. RNA isolated by using RNAzol or RNeasy Micro Kit yielded good quantity and quality of RNA for downstream applications compared to TRIzol. 40% PureSperm was found effective in removing somatic cells. RT-PCR results showed that sperm RNA samples were negative for CD4 and PTPRC. All the sperm RNA samples were positive for PRM and PLCZ1, markers of sperm RNA.

Effects of simulated hypo- and hyper-reproductive conditions on the characteristics of circadian rhythm in hypothalamic concentration of serotonin and dopamine and in plasma levels of thyroxine, triiodothyronine, and testosterone in Japanese quail, Coturnix coturnix japonica.

In this study, hypo‐ and hyper‐reproductive conditions, as measured by concentrations of plasma testosterone in male Japanese quail held on long days LD 16:8, were experimentally simulated with injections of 5‐hydroxytryptophan (5‐HTP) and L‐dihydroxyphenylalanine, (L‐DOPA) with 8 h and 12 h phase angle differences between them in intact and melatonin‐treated birds. The effects of these treatments were assessed on the characteristics of the circadian rhythm in the hypothalamic concentration of serotonin (5‐HT), dopamine (DA), and plasma levels of thyroxine (T4), triiodothyronine (T3), and testosterone (T). These rhythms were also studied in sham‐operated (SO), pinealectomized (Px), vehicle‐ (Veh), and melatonin (Mel)‐treated birds. On the basis of the circadian mesors of the testosterone rhythms, three distinct categories could be identified: category A (i.e., normal breeding concentrations of plasma testosterone), which includes control, sham‐operated, and vehicle‐treated groups; category A+ (i.e., concentrations of plasma testosterone higher than that found in normal breeding quail), which includes 12 h, 12 h+vehicle‐treated, and Px quails; and category A− (concentrations of plasma testosterone lower than that found in normal breeding quail), which includes 8 h, melatonin‐, and 12 h+melatonin‐treated groups. It is evident that in normal and hypergonadal conditions (i.e., birds belonging to categories A and A+) the circadian rhythm in hypothalamic serotonin maintained a positive phase angle of about 16 h. In contrast, birds of category A− (i.e., in a hypogonadal condition) exhibited a negative phase angle of about 2 h. The present results clearly suggest that the internal phase relationship between the circadian rhythms in hypothalamic serotonin and dopamine might play a crucial role in strategizing and conferring a particular reproductive status to the birds. The role of circadian mechanisms involving circulating thyroid hormones in conferring reproductive status is completely ruled out, as no definite internal phase angle between these two hormonal rhythms was witnessed vis‐à‐vis different treatment groups. The testosterone peaks always occurred at the same time irrespective of breeding status of the bird, but with significant variation in its amplitude (high in hypergonadal and low in hypogonadal condition). It is suggested that administration of 5‐HTP and L‐DOPA at specific time interval and variation in pineal functions that modulate reproductive responses also alter the circadian pattern (acrophase and amplitude) of hypothalamic serotonin and dopamine, maintaining a specific phase relation between these cycles and breeding status. These findings strengthen our previous reports that a specific circadian phase relation of serotonergic and dopaminergic oscillations regulates reproduction. The present study strongly supports interdependence and specific relation of the two systems (gonadal activity and circadian pattern/phase relation of neural oscillation) in both natural and experimentally simulated conditions.

Residues of fluoroquinolone drugs in the cloacal gland and other tissues of Japanese quail

1. In this study we investigated the residues of fluoroquinolone drugs (ciprofloxacin and pefloxacin) in the cloacal gland (a site of foam synthesis) and other tissues such as breast muscle, testes, brain, kidney and plasma. 2. Fifty-four healthy male Japanese quail were selected at random from a flock, maintained under uniform husbandry conditions and divided into three groups, each of 18 birds. Group I (control) received 1 ml vehicle (normal saline 0·9% (w/v) NaCl) daily for 12 d through the intraperitoneal route. Birds of groups II and III received ciprofloxacin and pefloxacin by the same route at the rate of 10 and 12 mg/kg body weight, respectively, every day for a similar period. 3. Birds from each group were killed, at 1, 5 and 10 d after the cessation of treatment, to collect the cloacal gland together with other tissues that were analysed for residual drugs. 4. Cloacal gland retained the maximum drug residues of ciprofloxacin (60%) and pefloxacin (80%) on d 10 compared with that on d 1 after drug withdrawal. The drug residues were found 60 and 80% in ciprofloxacin and pefloxacin groups, respectively, in the cloacal gland tissue even on d 10 after withdrawal of the treatment. 5. In the ciprofloxacin-treated group, all tissues except cloacal gland contained very small amounts of the drug residues on d 10 after treatment ended. In the pefloxacin group the cloacal gland, breast muscle and kidney retained a fairly high amount of drug even on d 10 after treatment ceased. No residues of pefloxacin were detectable in testes and brain throughout. 6. In conclusion, the cloacal gland in Japanese quail acted as the largest sink for the fluoroquinolone drugs. Ciprofloxacin was more widely distributed in different tissues and persisted for a shorter period than pefloxacin.

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.

Effect of Higher Levels of Dietary Vitamin E on Performance and Immune Response in Growing Japanese Quail

Abstract Biswas, A., Mohan, J., Sastry, K.V.H. and Tyagi, J.S. 2008. Effect of higher levels of dietary vitamin E on performance and immune responses in growing Japanese quail. J. Appl. Anim. Res., 33: 61–64. To study the effect of increasing dietary vitamin E (VE) on performance and immune response, 240 day old chicks were randomly selected and divided into 12 groups with 20 chicks in each group (3 dietary treatments × 4 replicates). The basal diet contained 15 IU VE/kg and the two experimental diets were supplemented with 150 IU and 300 IU VE/kg. Body weight gain, feed intake, feed conversion ratio and mortality were not affected by VE supplementation. Antibody titres, response to intradermally injected phytohaemagglutinin (PHA) and the relative weights of the bursa of Fabricius and thymus were significantly (P<0.05) higher after feeding the two VE-supplemented diets. It is concluded that VE supplementation improved immune response but not performance in growing Japanese quail.

Effect of Pinealectomy and Melatonin Administration on Jejunal Mucosal Enzymes and Performance of Young Broiler Chickens

Abstract Thakur, R., Tyagi, J.S., Mohan, J. and Sastry, K.V.H. 2006. Effect of pinealectomy and melatonin administration on jejunal mucosal enzymes and performance of young broiler chickens. J. Appl. Anim. Res., 30:137–140. To understand the role of gut melatonin on digestive enzymes and performance, day-old chicks (n=144) were divided into three groups i.e. control, sham operated and pinealectomised and kept under continuous light. Half of the birds from each group were administered melatonin (5mg/kg b wt) intraperitonealy, up to 20 days. Birds were sacrificed at d 10 and 20. Pinealectomy did not produce any significant variation while exogenous melatonin supplementation produced a significant increase (P<0.05) in mucosal amylase, trypsin and improved feed conversion ratio indicating that under continuous light exogenous melatonin had a positive effect on some jejunal mucosal enzymes.

Effect of seasonal variation on respiration rate and core body temperature in Aseel and Kadaknath breed of chicken

Native birds are more tolerant to adverse climatic conditions than the improved/cross-breeds of chicken. The present study was conducted to record the physiological responses such as respiration rate and body temperatures in Aseel and Kadaknath birds up to 6 weeks of age under standard managemental conditions during hot-humid and winter season. The dry-bulb temperature and wet-bulb temperature was recorded daily and temperature humidity index (THI) was calculated. The THI ranged from 73.33±1.61 to 85.70±0.33. Above 80 THI was observed during hot-humid season. The season, sex and breed interaction had highly significant (P<0.01) effect on body temperature (core and surface) and respiratory rate for all age groups. Season effect (P<0.05) was highly significant on studied parameters. It may be concluded that enhanced THI caused the elevation in surface and core body temperature along with increased respiration rate during hot-humid season, thereby indicating stressful conditions in native birds.