LYCOPENE- AND VITAMIN E-INDUCED MODULATION OF PHYSIOLOGICAL AND REPRODUCTIVE PERFORMANCE INDICES IN LAYING HENS DURING THE DRY SEASON

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dc.contributor.authorOBIDI, Joseph Ayodele
dc.date.accessioned2021-11-04T07:50:45Z
dc.date.available2021-11-04T07:50:45Z
dc.date.issued2021-03
dc.descriptionA DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN VETERINARY PHYSIOLOGY DEPARTMENT OF VETERINARY PHYSIOLOGY, FACULTY OF VETERINARY MEDICINE, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIAen_US
dc.description.abstractEnvironmental stress is progressively becoming a globally significant factor of concern to animal agriculture due to climate change.Variations in thermal environmental conditions in the tropical Guinea Savannah, especially when such changes are acute, frequent and abrupt constitute oxidative stress to animal well-being and productivity. The aim of the present study was to determine the ameliorative activity of supplemented lycopene (L) and vitamin E (VE) on thermal stress-induced changes in physiological and performance indices of laying hens during the harmattan and hot-dry seasons. Four hundred, apparently healthy laying hens, aged 41 weeks were divided into four groups each (n = 100): group 1 = L+VE, were coadministered with lycopene (30 mg⁄kg body weight) and vitamin E (250 mg ⁄ kg body weight); group 2 = L, were supplemented with lycopene only ((30 mg ⁄ kg body weight)); group 3 = VE were administered with vitamin E only (250 mg ⁄ kg body weight) and group 4 = CONTROL were not supplemented with any antioxidant. The antioxidants were administered for 5 weeks each, during the harmattan and hot-dry seasons. During the study period physiological and performace parameters were recorded daily and weekly. The results showed that thermal environmental conditions during the harmattan and hot-dry seasons were stressfull to the laying hens, but the hot-dry condition was more stressful to the birds. During the harmattan (cold-dry) season, laying birds were exposed to environmental stress ranging from cold to heat stressor. During the hot-dry season, laying birds were susceptible to severe heat stress almost all the day. The stressful conditions resulted in significant impairment in performance parameters of laying hens. A significant increase in percentage hen-day egg production was recorded in laying hens that were administered antioxidants, lycopene and vitamin E during the two seasons; however, it was evident that coadministration of L+VE to hens resulted in the most significant (P < 0.05) performance parameters. This was followed by laying birds that were administered with lycopene only and vitamin E only, respectively. Hen-day egg production parameter was lowest in control laying hens during the two seasons. Oestrogen and progesterone concentrations were significantly (P < 0.05) higher in antioxidant-administered groups of laying hens during the two seasons of the study. Results on thyroid function and thyroid hormone concentrations demonstrated that co-adminstration of lycopene and vitamin E was most significant on thyroid function during the two seasons, indicating that antioxidants surported thyroid function which is known to be dysfunctional during thermally-induced stress condition. Modulatory effect of thyroid hormones activity was more profound during the harmattan season, increasing cloacal temperatures(CTs) during the early hours of the day and decreasing CTs during periods commencing from 12:00 h. Modulatotory roles of antioxidants in the laying hens were in the order: L+VE > L > VE > CONTROL. Significant (P < 0.05) increase in CTs was recorded in L+ VE and L groups of laying hens during the study period. Results showed that the effect of VE on CTs was lower than in the former two groups. There was no significant (P > 0.05) difference in egg weight in experimental and control groups of laying hens during the seasons. However, internal and external egg parameters were significantly (P < 0.05) influenced by the supplementation of antioxidants where L+VE groups of laying hens recorded higher values in eggshell diameter. The group also showed a significant (P < 0.05) increase in egg albumen and yolk parameters. During the hot-dry season, ovarian function showed a more resilient aptitude in egg production. Countable white follicles and growing preovulatory yellow ovarian follicles were greater (P < 0.05) in number in antioxidant-administered laying hens. There was no transitional shelled egg in-uterus in any of the laying hens supplemented with antioxidants; only in control groups were shelled eggs-in-uteri prominent. It is concluded that the harmattan and hot-dry seasons were thermally stressful to laying hens. The administration of antioxidants lycopene and⁄or vitamin E ameliorated the effects of the stress and improved the welfare and productivity of the laying hens.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/12694
dc.language.isoenen_US
dc.subjectLYCOPENE- AND VITAMIN E-INDUCED MODULATION,en_US
dc.subjectPHYSIOLOGICAL,en_US
dc.subjectREPRODUCTIVE PERFORMANCE INDICES,en_US
dc.subjectLAYING HENS DURING,en_US
dc.subjectDRY SEASON.en_US
dc.titleLYCOPENE- AND VITAMIN E-INDUCED MODULATION OF PHYSIOLOGICAL AND REPRODUCTIVE PERFORMANCE INDICES IN LAYING HENS DURING THE DRY SEASONen_US
dc.typeThesisen_US
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