Effect of photoperiod on body weight gain, and daily energy intake and energy expenditure in Japanese quail (Coturnix c. japonica)

Withania somnifera inhibits photorefractoriness which triggers neuronal apoptosis in both pre-optic and paraventricular hypothalamic area of Coturnix coturnix japonica: involvement of oxidative stress induced p53 dependent Caspase-3 mediated low immunoreactivity of estrogen receptor alpha

Light has a very important function in the regulation of the normal physiology including the neuroendocrine system, biological rhythms, cognitive behavior, etc. The variation in photoperiod acts as a stressor due to imbalance in endogenous hormones. Estrogen and its receptors ER alpha and beta play a vital role in the control of stress response in birds. The study investigates the estrogenic effects of a well-known medicinal plant Withania somnifera (WS), mediated by estrogen receptor alpha (ERα) in the hypothalamic pre-optic area (POA) and paraventricular nuclei (PVN). Further the study elucidates its anti-oxidants and anti-apoptotic activities in the brain of Japanese quail. To validate this hypothesis, mature male quails were exposed to long day length for 3 months and then transferred to intermediate day length to become photorefractory (PR) while controls were still continued under long daylength. Supplementation of WS root extract in PR quail increases plasma estrogen and lowers corticosterone. Further, in PR quail the variation in light downregulates immunoreactivity of ERα, oxidative stress and antioxidant enzyme activities i.e. superoxide dismutase and catalase in the brain. Neuronal apoptosis was observed in the POA and PVN of PR quail as indicated by the abundant expression of Caspase-3 and p53 which reduces after the administration of WS root extract. The neuronal population also found to decrease in PR although it increased in WS administered quails. Further, the study concluded that change in photoperiod from 3 months exposure of 16L: 8D to 13.5L: 10.5D directly activates neuronal apoptosis via expression of Caspase3 and p53 expression in the brain and increases neuronal and gonadal oxidative stress while WS root extract reverses them via enhanced estrogen and its receptor ERα expression in the hypothalamic pre-optic and PVN area of Japanese quail.

Neural programming of seasonal physiology in birds and mammals: A modular perspective

Most animals in the temperate zone exhibit robust seasonal rhythms in neuroendocrine, physiological and behavioral processes. The integration of predictive and supplementary environmental cues (e.g., nutrients) involves a series of discrete, and interconnected brain regions that span hypothalamic, thalamic, mesencephalic, and limbic regions. Species-specific adaptive changes in these neuroendocrine structures and cellular plasticity have likely evolved to support seasonal life-history transitions. Despite significant advances in our understanding of ecological responses to predictive and supplementary environmental cues, there remains a paucity of literature on how these diverse cues impact the underlying neural and cellular substrates. To date, most scientific approach has focused on neuroendocrine responses to annual changes in daylength, referred to as photoperiod, due to the robust physiological changes to light manipulations in laboratory settings. In this review, we highlight the relatively few animal models that have been effectively used to investigate how predictive day lengths, and supplementary cues are integrated across hypothalamic nuclei, and discuss key findings of how seasonal rhythms in physiology are governed by adaptive neuroendocrine changes. We discuss how specific brain regions integrate environmental cues to form a complex multiunit or 'modular' system that has evolved to optimize the timing of seasonal physiology. Overall, the review aims to highlight the existence of a modular network of neural regions that independently contribute to timing seasonal physiology. This paper proposes that a multi-modular neuroendocrine system has evolved in which independent neural 'units' operate to support species-specific seasonal rhythms.

Influences of total sulfur amino acids and photoperiod on growth, carcass traits, blood parameters, meat quality and cecal microbial load of broilers

The current study aimed to discuss the impact of total sulfur amino acids (TSAA) %, photoperiod, and their interaction on growth performance, carcass and blood indices of broiler chicks. A total of 300 unsexed IR broiler chicks one-week old were used in a factorial arrangement (2 × 3), including two photoperiod systems (22 L: 2 D and 16 L: 8 D) and three experimental rations having three grades of Met + Cyst (TSAA) (70%, 85% and 100% of digestible lysine in starter and finisher diets). Results revealed that the higher LBW and BWG were noticed in birds given TSAA at grades of 1.1 or 0.90 % under 22L: 2D photoperiod at five weeks of age and the whole experimental period (1–5 weeks of age), respectively. The highest live body weight (LBW (and body weight gain (BWG) were recorded in birds received 1.1% TSAA under the long photoperiod compared to the control and the other groups. Birds fed 1.3% TSAA consumed more feed than the other groups. The opposite was found in birds fed 1.1% TSAA under the short photoperiod (16L: 8D). The best feed conversion (FCR) was detected by birds fed 1.1% and 0.90% TSAA diets during the whole experimental period. All carcass traits studied were significantly influenced by TSAA levels, except for the relative weights of abdominal fat and spleen. The interaction effect on was significant on all carcass traits except spleen %. In conclusion, the addition of TSAA at level 1.1 and 0.9 % to starter and finisher diets under a long photoperiod regime improved broiler’s performance, carcass traits, and blood parameters studied.

Pleiotropic effects of proopiomelanocortin and VGF nerve growth factor inducible neuropeptides for the long-term regulation of energy balance

Seasonal rhythms in energy balance are well documented across temperate and equatorial zones animals. The long-term regulated changes in seasonal physiology consists of a rheostatic system that is essential to successful time annual cycles in reproduction, hibernation, torpor, and migration. Most animals use the annual change in photoperiod as a reliable and robust environmental cue to entrain endogenous (i.e. circannual) rhythms. Research over the past few decades has predominantly examined the role of first order neuroendocrine peptides for the rheostatic changes in energy balance. These anorexigenic and orexigenic neuropeptides in the arcuate nucleus include neuropeptide y (Npy), agouti-related peptide (Agrp), cocaine and amphetamine related transcript (Cart) and pro-opiomelanocortin (Pomc). Recent studies also indicate that VGF nerve growth factor inducible (Vgf) in the arcuate nucleus is involved in the seasonal regulation of energy balance. In situ hybridization, qPCR and RNA-sequencing studies have identified that Pomc expression across fish, avian and mammalian species, is a neuroendocrine marker that reflects seasonal energetic states. Here we highlight that long-term changes in arcuate Pomc and Vgf expression is conserved across species and may provide rheostatic regulation of seasonal energy balance.

The Versatile Tanycyte: A Hypothalamic Integrator of Reproduction and Energy Metabolism

The fertility and survival of an individual rely on the ability of the periphery to promptly, effectively, and reproducibly communicate with brain neural networks that control reproduction, food intake, and energy homeostasis. Tanycytes, a specialized glial cell type lining the wall of the third ventricle in the median eminence of the hypothalamus, appear to act as the linchpin of these processes by dynamically controlling the secretion of neuropeptides into the portal vasculature by hypothalamic neurons and regulating blood-brain and blood-cerebrospinal fluid exchanges, both processes that depend on the ability of these cells to adapt their morphology to the physiological state of the individual. In addition to their barrier properties, tanycytes possess the ability to sense blood glucose levels, and play a fundamental and active role in shuttling circulating metabolic signals to hypothalamic neurons that control food intake. Moreover, accumulating data suggest that, in keeping with their putative descent from radial glial cells, tanycytes are endowed with neural stem cell properties and may respond to dietary or reproductive cues by modulating hypothalamic neurogenesis. Tanycytes could thus constitute the missing link in the loop connecting behavior, hormonal changes, signal transduction, central neuronal activation and, finally, behavior again. In this article, we will examine these recent advances in the understanding of tanycytic plasticity and function in the hypothalamus and the underlying molecular mechanisms. We will also discuss the putative involvement and therapeutic potential of hypothalamic tanycytes in metabolic and fertility disorders.

Neuroendocrine mechanism of food intake and energy regulation in Japanese quail under differential simulated photoperiodic conditions: Involvement of hypothalamic neuropeptides, AMPK, insulin and adiponectin receptors

Neuroendocrine coordination between the reproductive and energy regulatory hypothalamic circuitries not only tightly regulates food intake and energy expenditure but also maintains the body weight and reproduction. The effect of different simulated photoperiodic conditions on food intake and neuroendocrine mechanism of energy homeostasis in Japanese quail is not investigated till date. Hence, our present study is designed to elucidate the effect of different simulated photoperiodic conditions on food consumption and neuroendocrine mechanism(s) of energy regulation in this poultry species. The alterations in hypothalamic energy balancing neuropeptides (NPY/AgRP/CART), polypeptide hormone precursor (POMC), protein kinase (AMPK-p-AMPK) as well as receptors of insulin and adiponectin [Insulin Receptor (IR), Adiponectin Receptor 1 & 2] have been investigated in photosensitive (PS), scotorefractory (SR),photorefractory (PR) and scotosensitive (SS) quail. Immunofluorescence and western blotting were used to quantify the expression of these peptides and proteins. Results showed increased food consumption and body weight gain, along with increased expression of NPY, AgRP, IR, adiponectin receptors and p-AMPK, decreased CART and POMC in the hypothalamus of photosensitive and scotorefractory quail. While, opposite findings were observed in photorefractory and scotosensitive quail. Hence, this study may suggest the hypothalamic energy channelization towards reproductive axis in photosensitive and scotorefractory quail to support the full breeding conditions, while hypothalamic energy deprivation in photorefractory and scotosensitive quail leads to reproductive quiescence.

Lighting programs for male and female meat quails (Coturnix coturnix) raised in equatorial region

The aim of the present study was to evaluate the effect of lighting programs for male and female meat quails raised in an equatorial region on performance and carcass traits. A total of 1,500 sexed quails (Coturnix coturnix) was distributed in a completely randomized design in a 2 × 3 factorial arrangement, with 2 sexes (male and female) and 3 lighting programs (natural, intermittent, and continuous) with 5 replicates of 50 birds. The lighting programs were applied in the period from 7 to 49 d of age, being natural (12 h and 30 min of natural light and 11 h and 30 min of dark), intermittent (12 h and 30 min of natural light and 5 h and 30 min of artificial light, alternating lighting periods with one h and 06 min and periods of darkness with one h and 12 min), and continuous (23 h of natural + artificial light and one h of dark). Regardless of lighting program, female quails were heavier than males, and birds subjected to natural light weighed less than those exposed to continuous and intermittent lighting programs. Quails exposed to intermittent and continuous light presented higher weight gain and feed intake, and worse feed conversion ratio compared to birds under a natural light regimen. It is concluded that in an equatorial region, it is possible to use a lighting program with only natural light for raising male and female meat quails from 7 to 49 d of age.

Basing Turkey Lighting Programs on Broiler Research: A Good Idea? A Comparison of 18 Daylength Effects on Broiler and Turkey Welfare

Simple Summary

Altering daylength in a poultry management program is a simple tool that can have immense impacts on productivity and bird welfare. It is not uncommon for lighting data derived from broiler research to be extrapolated to turkey production. This review of two studies (one with broilers and the second with turkeys), completed in the same research facility using the same lighting programs, shows evidence that some, but not all responses to graded daylengths are similar between these two species. It defines that daylength choices for turkeys should be based on research conducted with turkeys.

Abstract

Daylength used as a management tool has powerful implications on the welfare of both broilers and turkeys. Near-constant light results in many detrimental impacts, including lack of behavioural rhythms and circadian melatonin rhythms. Both are suggestive that sleep fragmentation could result in birds reared on long photoperiods, which can lead to the same negative health and physiological responses as total sleep deprivation. An indirect comparison of the welfare implications of graded levels of daylength on broilers and turkeys clearly indicate that long daylengths depress welfare by increasing mortality, reducing mobility, increasing ocular pathologies and changing behaviour in both species. Furthermore, long daylengths change melatonin secretion patterns and eliminate behavioural and melatonin circadian rhythms, which were measured in broilers in these works. However, feather pecking in turkeys was reduced when birds were exposed to long daylengths. Exactly how much darkness should be included in a management program to maximize welfare will depend on the species, the age of marketing, and in turkeys, bird gender.

Growth performance, meat quality traits, and genetic mapping of quantitative trait loci in 3 generations of Japanese quail populations (Coturnix japonica)

The current research was conducted to compare growth, carcass traits, pH, intramuscular collagen (IMC) properties, and genetic bases of IMC and carcasses (breast-muscle weight) of different lines and generations of adult males and females of Japanese quail (Coturnix japonica). Forty-four quails (generation F0), 22 Pharaoh (F-33) meat-type males and 22 Standard (S-22) laying-type females, were crossed to produce the F1 hybrids generation. The F2 generation was created by mating one F1 male with one F1 female, full siblings. The birds, randomly chosen from F0 (22 males and 22 females), F1 (22 males and 22 females), and F2 (84 males and 152 females) were raised to 20 wk of age in collective cages. Quails were fed ad libitum commercial diets. At slaughter, all birds were individually weighed (after a fasting period of 12 h) and dressing yield (without giblets) was calculated. The carcasses were then dissected. Genomic DNA was extracted from all of the blood, and 30 microsatellite markers located on 2 quail chromosomes were genotyped. The F -: 33 quails had higher in vivo and postmortem performances and a higher abdominal fat percentage than those of the egg line. Meat from S -: 22 quails had a slower collagen maturation (hydroxylysylpyridinoline crosslink/collagen) and a higher ultimate pH. The F1 and F2 generations showed an evident sexual dimorphism, and an additional effect could be due to hybrid heterosis evident in F2. Meat from quails of F1 and F2 generations had a lower IMC amount with a higher degree of collagen maturation compared with parental lines. Two statistically significant QTL have been detected on quail chromosome 2 (CJA02): a QTL with an additive effect (0.50) for IMC in the marker bracket GUJ0037 and GUJ0093; a second QTL with additive (1.32) and dominant (1.91) effects for breast-muscle weight in the marker bracket GUJ0084 and GUJ0073. To our knowledge, this is the first report of a QTL associated with breast-muscle weight and IMC in quail and poultry species, respectively.

Effects of temperature acclimation on body mass and energy budget in the Chinese bulbul Pycnonotus sinensis

Chinese bulbuls (Pycnonotus sinensis) are small passerine birds that inhabit areas of central, southern and eastern China. Previous observations suggest that free-living individuals of this species may change their food intake in response to seasonal changes in ambient temperature. In the present study, we randomly assigned Chinese bulbuls to either a 30℃ or 10℃ group, and measured their body mass (BM), body temperature, gross energy intake (GEI), digestible energy intake (DEI), and the length and mass of their digestive tracts over 28 days of acclimation at these temperatures. As predicted, birds in the 30℃ group had lower body mass, GEI and DEI relative to those in the 10℃ group. The length and mass of the digestive tract was also lower in the 30℃ group and trends in these parameters were positively correlated with BM, GEI and DEI. These results suggest that Chinese bulbuls reduced their absolute energy demands at relatively high temperatures by decreasing their body mass, GEI and DEI, and digestive tract size.

Effects of social cues on GnRH-I, GnRH-II, and reproductive physiology in female house sparrows (Passer domesticus)

In all vertebrates, at least two forms of gonadotropin-releasing hormone (GnRH) are present: GnRH-I and GnRH-II. GnRH-I directly influences the reproductive axis whereas the function of GnRH-II is less clear. The present experimental objectives were to determine the effect(s) of male social cues on the peripheral and neural responses of female house sparrows (Passer domesticus). We hypothesized that male breeding status would significantly influence the amount of immunoreactive GnRH-II in female house sparrow brains. In order to test this hypothesis, females were caged with a breeding male, a non-breeding male, or caged alone. The presence of breeding males did not significantly influence ovary development, luteinizing hormone, or estradiol levels, but male presence increased female body mass, and male presence and condition interacted to influence ovarian follicle size. Using immunocytochemistry, GnRH-I and GnRH-II immunoreactivity was measured in order to evaluate the neuroendocrine response to breeding status in males. When females were housed with breeding males, there were stable numbers of immunoreactive GnRH-I and -II cells but significantly lower amounts of immunoreactive GnRH-I fibre staining within the preoptic area compared to females housed with non-breeding males. Moreover, immunoreactive GnRH-II fibres in the preoptic area, ventromedial nucleus, and medial septum were significantly greater in females housed alone in chamber with non-breeding males. The data demonstrate that the GnRH system in songbirds is modulated by social context. These finding provide novel insight into the mechanisms involved with regulating avian reproductive physiology.

Photoperiodic changes in hypothalamic insulin receptor gene expression are regulated by gonadal testosterone

In order to adapt to seasonal changes, animals exhibit robust changes in their reproductive status, body weight, and molt. However, the molecular mechanisms regulating such seasonal changes in physiology and behavior are not fully understood. Here, we report the photoperiodic regulation of the insulin receptor (IR) gene in the infundibular nucleus (anatomically homologous to the mammalian arcuate nucleus) of the Japanese quail. When the birds were transferred from short-day to long-day conditions, a significant increase in the level of IR mRNA was observed on the 10th long day, whereas that in testicular length was observed on the 5th long day. Castration abolished IR mRNA expression induced by long-day conditions, whereas the testosterone administration mimicked induction of IR mRNA expression induced by long-day conditions. These results suggested that the photoperiodic regulation of the IR mRNA in the infundibular nucleus is mediated by testosterone from the testes. It has been known that the central administration of insulin increases luteinizing hormone (LH) secretion, and neuron-specific disruption of IR gene causes impaired gonadal function due to the dysregulation of LH and increased food intake and body weight. Together with these results, the photoperiodic regulation of the IR mRNA in the hypothalamus may enhance the effect of long days in the seasonal response of reproduction and body weight changes.

Differential effects of 4 types of environmental enrichment on aggressive pecking, feather pecking, feather loss, food wastage and productivity in Japanese quail

1. We examined the effects of 4 types of environmental enrichment (foraging opportunities, structural complexity, sensory stimulation/novelty, and social companionship) on aggressive and feather pecking, feather condition, food wastage, body weight, feed conversion, and egg production in adult Japanese quail. Sex differences were examined where possible. 2. GLM analysis was used to evaluate the effects of enrichment and housing, while test-retest reliability and the stability of measures over 18 d were assessed using partial correlation. 3. Foraging enrichment reduced food wastage. 4. Body weight, feed conversion, and egg production were not affected by enrichment. Rates of aggressive and feather pecking were also not significantly affected, but these behaviours were observed very infrequently in this study. 5. Socially-housed birds had poorer feather condition, lower body weight and less efficient feed conversion than singly-housed birds. Social housing did not affect food wastage. 6. There were not sex differences in feather pecking, feather condition, food wastage, or feed conversion. 7. All measures except feather pecking were reliable over 24 h, but only feather condition and body weight were stable over 18 d. The instability f the behavioural measures over time suggest that enrichment effects may vary with age.

Foraging behavior and physiological changes in precocial quail chicks in response to low temperatures

We examined whether low ambient temperatures influence foraging behavior of precocial Japanese quail chicks and alter the balance between investment in growth and thermogenic function. To test this, one group of chicks was exposed to 7 degrees C and one group to 24 degrees C during foraging throughout the developmental stage. Chicks adapted well to the temperatures through a high flexibility in behavior and physiological development. In response to cold, chicks shortened foraging bout lengths two- to sixfold, and increased cycle lengths (i.e. length of a brooding bout plus subsequent foraging bout), resulting in a decrease in total foraging time. Body temperature during foraging was lower in cold-exposed chicks but did not drop below 37.8 degrees C, suggesting that the direct cause to end a foraging bout was not body temperature. The metabolic rate of cold-exposed chicks was reduced by 48% to 60% when switching from foraging to brooding, which may be an important factor in determining foraging behavior of precocial chicks. Mass-specific food intake of the cold-exposed chicks exceeded that of warm chicks by 15%. Cold-exposed chicks doubled foraging efficiency to reach this intake during their reduced foraging time. Metabolic rates initially were similar in both groups, but increased rapidly and were elevated in cold-exposed chicks from 15 days of age onward. Growth rate initially was reduced in cold-exposed chicks, and exceeded growth of warm chicks only after 21 days of age. These results suggest that in response to cold, a shift occurs in the balance between growth rate and thermoregulatory function in favor of thermoregulatory function.

Validation of the DLW method in Japanese quail at different water fluxes using laser and IRMS

In Japanese quail (Coturnix c. japonica; n = 9), the doubly labeled water (DLW) method ((2)H, (18)O) for estimation of CO(2) production (l/day) was validated. To evaluate its sensitivity to water efflux levels (r(H(2))O(e); g/day) and to assumptions of fractional evaporative water loss (x; dimensionless), animals were repeatedly fed a dry pellet diet (average r(H(2))O(e) of 34.8 g/day) or a wet mash diet (95.8 g/day). We simultaneously compared the novel infrared laser spectrometry (LS) with isotope ratio mass spectrometry. At low r(H(2))O(e), calculated CO(2) production rate exhibited little sensitivity to assumptions concerning x, with the best fit being found at 0.51, and only little error was made employing an x value of 0.25. In contrast, at high r(H(2))O(e), sensitivities were much higher with the best fit at x = 0.32. Conclusions derived from isotope ratio mass spectrometry and LS were similar, proving the usefulness of LS. Within a threefold range of r(H(2))O(e), little error in the DLW method is made when assuming one single x value of 0.25 (recommended by Speakman JR, Doubly Labelled Water. Theory and Practice. London: Chapman & Hall, 1997), indicating its robustness in comparative studies.

Day length has a major effect on the response of protein synthesis rates to feeding in growing Japanese quail

We investigated the effect of day length on mixed protein fractional synthesis rates (K(S)) in 14- and 21-d-old Japanese quail (Coturnix c. japonica) habituated to either a long day length, 18 h light/6 h dark (LDL), or short day length, 6 h light/18 h dark (SDL), with free access to food during the light period. Rates of protein synthesis were measured by a flooding dose of L-[1-(13)C]leucine. In both groups, we measured K(S) of pectoral muscle, liver and heart after an overnight period of food deprivation and after 2-h food access at dawn. Rates of protein synthesis were also measured in LDL quail starved for 18 h and refed for 2 h. SDL chicks were smaller and had lower tissue weights at 2 wk of age than did LDL chicks (P<0.05). Starvation led to a lower rate of protein synthesis in those animals starved for 18 h. Food availability after starvation for 18 h induced a significant rise in tissue protein synthesis in both SDL and LDL quail (P<0.05). This increase was absent in LDL quail after a 6-h starvation period. There was an increase in K(S) to ad hoc changes in food supply. By determining the daily period in which feeding can occur, day length has a major effect on protein synthesis rates. This effect will determine the overall growth chicks are able to achieve that have been subjected to different day lengths.

The effect of food restriction on morphological and metabolic development in two lines of growing Japanese quail chicks

To investigate whether there is a relationship between the inherent maximum growth rate of a chick and its degree of developmental plasticity, we studied the effects of food restriction on morphological and physiological development in P-line (selected for high growth rates) and C-line (nonselected) chicks of the Japanese quail between 2 and 64 d of age. In each line, three groups were created; one group in which the chicks were fed ad lib. and two other groups in which the chicks received 70% and 40% of the line-specific ad lib. feeding levels, respectively. In all three groups, chick survival rates were very high, and no relationship was detected between feeding level and chick mortality. The experimental feeding levels strongly affected the chicks' attainment of body mass at all ages. In addition, at most ages the growth of the structural components (wing, tarsus, and head) were also significantly affected by the feeding experiment but to a much smaller extent than the body mass. The feeding levels also affected the achievement of female sexual maturity such that, at the end of the experiment, most of the ad lib.-fed females and none of the females that received 40% of the ad lib. feeding level were laying eggs. In chicks of both lines that were fed ad lib., homeothermy was achieved at 7 d of age, but in chicks that received 40% of the line-specific ad lib. levels, homeothermy was achieved after 15-22 d of age. Poikilothermic chicks (P- and C-line) that were relatively heavy for their age exhibited relatively high resting metabolic rates (RMRs) and peak metabolic rates (PMRs) for their age. In addition, a positive relationship was found between the chicks' relative mass and RMR (based on mass-based predictive equations). No relationship was detected between the chicks' relative body mass and their relative PMR (relative to mass-based predictive equations). With respect to the metabolic scope (i.e., PMR-RMR), Japanese quail chicks exhibited remarkable developmental plasticity: chicks with body masses that were 50% lower than the normal growing chicks did exhibit a normal capacity of thermogenic heat production for their mass. Because no differences were found with respect to the level of plasticity of morphological and physiological development between the two strains, we conclude that the selection for high postnatal growth rates in P-strain chicks has not resulted in a in a higher vulnerability of these chicks to food restrictions.