Impact of Food Restriction on Ovarian Development,RFamide‐Related Peptide‐3 and the Hypothalamic–Pituitary–Ovarian Axis in Pre‐Pubertal Ewes

RFamide‐related peptide‐3 (RFRP‐3), the mammalian ortholog of gonadotropin‐inhibiting hormone, has been implicated as a mediator between reproduction and energy balance. This study aimed to investigate the physiological effects of RFRP‐3 on the process of ovarian development in food‐restricted pre‐pubertal ewes. The results showed that food restriction significantly inhibited the ovarian development and follicular growth. The data of qPCR in the hypothalamic–pituitary–ovarian (HPO) axis showed that food restriction not only upregulated RFRP‐3 mRNA expression but also downregulated the mRNA expression of gonadotropin‐releasing‐hormone receptor, follicle‐stimulating hormone receptor and luteinizing hormone receptor (LHR). Immunohistochemistry of RFRP‐3 in the ovaries suggested that RFRP‐3 may regulate the follicular development. These results suggested that the changes of RFRP‐3 in response to food restriction might influence the HPO axis and inhibit ovarian development.     

Expression and localization of adiponectin and its receptors in ovarian follicles during different stages of development and the modulatory effect of adiponectin on steroid production in water buffalo

Adiponectin is an adipocyte‐derived hormone regulating energy metabolism, insulin sensitivity and recently found to regulate reproduction. The current study was carried out to investigate gene and protein expression, immunolocalization of adiponectin and its receptors AdipoR1 and AdipoR2 in ovarian follicles of different developmental stages in water buffalo (Bubalus bubalis) and to investigate the effect of adiponectin on steroid production in cultured bubaline granulosa cells. qPCR, western blotting and immunohistochemistry were applied to demonstrate mRNA expression, protein expression and immunolocalization, respectively. The results indicate that adiponectin, AdipoR1 and AdipoR2 were present in granulosa cells (GC) and theca interna (TI) of ovarian follicles and the expression of adiponectin, AdipoR1, AdipoR2 in GC and AdipoR1 and AdipoR2 in TI increased with increase in follicle size (p < .05). Expression of adiponectin was high in small and medium size follicles in TI. The adiponectin and its receptors were immunolocalized in the cytoplasm of GC and TI cells. Further, in the in‐vitro study, GCs were cultured and treated with recombinant adiponectin each at 0, 1 and 10 µg/ml alone or with follicle stimulating hormone (FSH) at 30 ng/ml) or Insulin‐like growth factor I (IGF‐I) at 10 ng/ml for 48 hr after obtaining 75%–80%s confluency. Adiponectin at 10 µg/ml increased IGF‐I‐induced estradiol (E₂) and progesterone (P₄) secretion and FSH‐induced E₂ secretion from GC and also increased the abundance of factors involved in E₂ and P₄ production (cytochrome P45019A1 [CYP19A1] and 3‐beta‐hydroxysteroid dehydrogenase [3β‐HSD]). In conclusion, this study provides novel evidence for the presence of adiponectin and its receptors in ovarian follicles and modulatory role of adiponectin on steroid production in buffalo.     

Energy requirements of early‐weaned Dorper cross‐bred female lambs

The net and metabolizable energy (NE and ME) requirements of Dorper cross‐bred female lambs with BWs of 20–35 kg were assessed in a comparative slaughter trial. Thirty‐five Dorper × thin‐tailed Han cross‐bred female lambs weaned at ~50 days of age (20.3 ± 2.15 kg BW) were used. Seven randomly selected lambs were slaughtered at the start of the trial (baseline group). An intermediate group consisting of seven randomly selected lambs fed ad libitum was slaughtered when the lambs reached an average BW of 28.5 kg. The remaining 21 lambs were allotted randomly to three levels of dry matter intake: ad libitum or restricted to 70% or 40% of the ad libitum intake. All the lambs were slaughtered when the sheep fed ad libitum reached a BW of 35 kg. Total body energy, nitrogen, fat, ash and moisture content were determined. In a digestibility trial, an additional 15 Dorper × thin‐tailed Han cross‐bred female lambs (28.7 ± 1.75 kg BW) were housed in metabolism cages and used in a completely randomized design experiment to evaluate the ME value of the diet at the three feed intake levels. The maintenance requirements for NE and ME were 245.5 and 380.3 kJ/kg metabolic shrunk body weight (SBW^0.75) respectively. The partial efficiency of energy use for maintenance was 0.645. The NE requirements for growth ranged from 1.18 to 5.18 MJ/d for the lambs gaining 100–350 g/d from 20 to 35 kg BW. Partial efficiency of ME for growth was 0.44. In conclusion, the current study suggests that the NE requirement for maintenance and growth of Dorper early‐weaned cross‐bred female lambs is lower than the current AFRC and NRC recommendations.     

Adiponectin‐impaired adipocyte differentiation negatively regulates fat deposition in chicken

Adiponectin is a protein hormone secreted exclusively by adipocytes that plays an important role in the modulation of glucose and lipid metabolism. To investigate the effect of adiponectin on lipid metabolism in chicken, rosiglitazone (agonist of adiponectin) and dexamethasone (inhibitor of adiponectin) were used to treat 23‐day‐old broilers in vivo. To verify the functionality of adiponectin on fat deposition, chicken pre‐adipocytes were cultured in the medium containing 10 μg/ml adiponectin. Serum adiponectin and lipids and fat distribution were analysed. Oil Red O staining was used to determine lipid deposition in adipocytes. The expression levels of adiponectin, adiponectin receptors (AdipoR) and lipid metabolism–related genes in different tissues and pre‐adipocytes were measured using real‐time PCR, and the abundance of lipid metabolism–related proteins was measured by Western blot. Rosiglitazone increased serum adiponectin concentration and the expression levels of adiponectin and adiponectin receptor 1 (AdipoR1) in tissues and significantly decreased levels of serum lipids and fat deposition. Rosiglitazone significantly increased the expression levels of adipose triglyceride lipase (ATGL) and AdipoR1 and decreased the expression levels of fatty acid synthase (FAS). Dexamethasone had the converse effects compared with rosiglitazone. Oil red O staining results showed a marked decrease in fat deposition in cells treated with adiponectin. In adipocytes, adiponectin could decrease the expression levels of CCAAT/enhancer‐binding protein α (C/EBPα) and FAS and increased the expression levels of ATGL and AdipoR1. These results indicate that adiponectin has a remarkable effect on impairment of adipocyte differentiation, which contributes to the negative regulation of fat deposition in chicken.     

Effects of Female Dietary Restriction in a Rabbit Growth Line During Rearing on Reproductive Performance and Embryo Quality

Maternal diet prior to mating has an effect on reproductive performance. We analysed the effect of maternal dietary restriction during rearing on reproductive performance, the embryo development and foetal growth. Females were categorized in two groups: (i) does with ad libitum access to feed or (ii) restricted. Two experiments were performed: (i) after 1 month, receptive females from both experimental groups were artificially inseminated and the reproductive performance was recorded during three reproductive cycles; at the first insemination, the body weight and perirenal fat thickness were recorded, and (ii) females from both experimental groups were inseminated, and 24 h later, embryos were recovered and transferred to recipient females from a maternal line. Later, embryonic implantation was assessed at day 14 by laparoscopy and foetal growth was monitored by ultrasound examination. In experiment 1, no differences in kindling rate was found, but prolificacy was showed to be higher in ad libitum does, which also were heavier than restricted ones. In experiment 2, no differences among does either in body weight, in perirenal fat thickness or in reproductive performance (ovulation rate and embryo recovery rate) were related to differences in feed intake. However, despite similar embryonic implantation losses, embryos from restricted females demonstrated higher foetal and gestational losses. Embryos from restricted does presented lower foetal growth than embryos from ad libitum does. Therefore, our results demonstrated that nutrition before first conception in a rabbit line selected for growth rate may impact on the embryo and results in a disturbance in gestational losses and foetal growth over all reproductive life.     

Effect of supplements during the cold season on the reproductive system in prepubertal Tibetan sheep ewes

We examined the development of the reproductive system in prepubertal Tibetan sheep ewes when fed only oat hay (CON) or supplemented with either lick blocks (BS) or concentrate feed (CS) during the cold season. The average daily gain of the CS ewes was greater than that of the BS ewes (P  < 0.05), which was greater than that of the CON ewes. The same pattern was observed in the number of ovarian follicles (P  < 0.001), that is, CS > BS > CON. Serum concentrations of gonadotropin‐releasing hormone, follicle‐stimulating hormone, luteotrophic hormone, estradiol and progesterone in the CS and BS groups were higher than in the CON group (P  < 0.05). The messenger RNA (mRNA) expression of KiSS‐1, GPR54 (G protein‐coupled receptor 54), ERα (estradiol receptor α) in the hypothalamic anteroventral periventricular area of the CS group were higher than in both the BS and CON groups (P  < 0.05), while the BS group was higher than in the CON group (P  < 0.05). Similar differences among groups were observed for gonadotropin‐releasing hormone receptor mRNA expression in the pituitary, follicle‐stimulating hormone receptor and luteinizing hormone receptor mRNA expression in the ovary. These results indicated that the KiSS1/GPR54 system was more active with nutrition or trace mineral supplementation during the cold season. The system stimulated the hypothalamic–pituitary?gonadal axis and enhanced folliclar development in prepubertal Tibetan sheep ewes. We concluded that energy, protein and trace minerals supplements could improve the reproductive performance of Tibetan sheep on the Qinghai‐Tibetan plateau.     

Energy and protein requirements of weaned male and female Saanen goats

The objective of this research was to estimate the energy and protein requirements for maintenance and growth in male (castrated and intact) and female Saanen goat kids between 15 and 30 kg BW. To determine the net energy requirements for maintenance (NE_m) and the net protein requirements for maintenance (NP_m), 75 goats (25 castrated and 26 intact males and 24 females) were used. Twenty‐one goats (seven castrated and eight intact males and six females) were randomly assigned for slaughter to estimate the initial empty body composition. The 54 remaining animals (18 castrated and 18 intact males and 18 females) were randomly assigned in a split‐plot design using a 3 × 3 factorial arrangement with three sexes and three levels of intake (ad libitum and restricted feed to 75% or 50% of the ad libitum intake). Within each sex, six blocks (three goats per block) were formed and one goat was randomly assigned to each level of intake. The 75% and the 50% of ad libitum rationing were determined daily, based on the DMI of the animal fed ad libitum on the previous day. All animals within block were slaughtered when the animal fed ad libitum reached 30 kg BW. The net energy requirements for gain (NE_g) and the net protein requirements for gain (NP_g) were obtained using 58 animals (20 castrated and 20 intact males and 18 females). The animals were fed ad libitum and slaughtered at targeted BW (15, 23 or 30 kg). Sex did not affect NE_g and NP_m (277.8 kJ/kg^0.75 BW day and 2.98 g CP/kg^0.75 BW day respectively), as well as NP_g (180.9 ± 6.48 g/kg EBW gain) in Saanen goat kids. However, castrated males and females had similar NE_g (varied from 12.6 ± 0.424 to 17.9 ± 1.38 MJ/kg EBW gain), greater than intact males (varied from 9.74 ± 0.420 to 10.7 ± 0.984 MJ/kg EBW gain), as the BW increased from 15 to 30 kg.     

Alternate‐day fasting diet improves fructose‐induced insulin resistance in mice

Increased fructose consumption is linked to insulin resistance, weight gain, hyperlipidemia and hypertension. Although the advantages of several dietary restriction regimens have been demonstrated, the effects of alternate‐day fasting (ADF) on fructose‐induced insulin resistance have not yet been studied. This study is based on a new modification on ADF by combining the fructose‐rich solution (10% w/v) and regular mice diet. Mice were randomly allocated into four groups: ADF50% (50% restriction in chow food intake but ad libitum fructose drink), ADF100% (100% restriction for chow food but ad libitum fructose drink), control (ad libitum chow food intake plus tap water) and daily food and fructose (DFF) (had free access to both chow and fructose solution). Biweekly fasting blood sugar (FBS), glucose tolerance test (GTT) and insulin tolerance test (ITT) were conducted. All groups gained weight during the study (p < 0.05). Body weights of DFF and control groups did not differ from that of ADF groups, but ADF50% gained more (p < 0.01) weights than ADF100% through the study. Total calorie intake (feed + fast days) of ADF50% was higher than that of ADF100% (p < 0.001) and control (p < 0.03). In addition, ADF groups consumed more energy than the control and DFF groups in feed (ad libitum) days (p < 0.05). At the end of the study, the mean FBS levels in the control and ADF100% groups were similar and significantly lower in relation to that of DFF and ADF50% groups (p < 0.01). Measurements of area under the curve in GTT and ITT revealed that the ADF100% group was more insulin‐sensitive than the DFF and ADF50% groups. In conclusion, these data suggest that the ADF100% improves fructose‐induced insulin resistance in mice.     

Energy requirements for growth of pubertal female Saanen goats

Previous research on energy requirements of female Saanen goats, using the factorial approach, has not considered the specific requirements for maintenance and growth during the pubertal phase. Thus, the purpose of this study was to estimate energy requirements for maintenance (Trial 1) and growth (Trial 2) of non‐pregnant and non‐lactating female Saanen goats at the pubertal phase from 30 to 45 kg. In Trial 1, the net energy requirements for maintenance (NE_m) were estimated using 18 female Saanen goats randomly assigned to three levels of intake: ad libitum, and 70% and 40% of ad libitum intake. These animals were pair‐fed in six slaughter groups, each consisting of one animal for each level of intake. In Trial 2, the net energy requirements for growth (NE_g) were estimated using 18 female Saanen goats, which were fed ad libitum and slaughtered at targeted BW of 30, 38 and 45 kg. The NE_m was 52 kcal/kg^0.75 of BW. The NE_g increased from 3.5 to 4.7 Mcal/kg of BW gain as BW increased from 30 to 45 kg. Our results suggest that the guidelines of the major feeding systems for the entire growth phase may not be adequate for females at pubertal phase.     

Effect of system of lamb rearing and season on early post‐partum fertility of ewes and growth performance of lambs in Katahdin sheep

The effect of season (S), lamb rearing system (RT) and grain supplementation (GS) on post‐partum fertility in Katahdin ewes and growth in Katahdin lambs was evaluated. Katahdin ewes were bred to lamb in fall (n = 36) or spring (n = 56) and at approximately 2.5 months post‐partum were randomly assigned to be permanently separated or to continue to suckle their lambs for an additional 3 months. All ewes were joined with rams following treatment to synchronize oestrus. Weaned (W, n = 84) and continuously suckled lambs (CSK, n = 88) were fed forage only (n = 84; hay and pasture for fall‐ and spring‐born lambs respectively) or were supplemented (n = 88; 18% crude protein ration ad libitum) and all weighed biweekly. Ewes rebred in the fall had a shorter ram introduction to lambing interval (p < 0.05), higher prolificacy (p = 0.001) and higher lambing rates (p = 0.02); however, the proportion of ewes lambing was not affected by season. The first service lambing rate was lower in ewes continuously suckling lambs in the spring, but not in the fall breeding season (S × RT, p = 0.03). Lambs that continuously suckled their dams and were supplemented grew quicker and gained more (p < 0.001) than their weaned and unsupplemented counterparts. The effect of CSK on growth rate of lambs was greater in the spring (RT × S; p = 0.05), and the effect of supplementation on growth rate of lambs was greater in the fall (GS × S; p < 0.0001). In conclusion, Katahdin lambs achieved higher weight gains from continuous suckling and grain supplementation. Moreover, Katahdin ewes are capable of early rebreeding post‐partum while suckling their lambs, which makes them suited for use in accelerated lambing programmes.     

Expression of Adiponectin and its Receptors in the Porcine Hypothalamus During the Oestrous Cycle

Adiponectin is a hormonal link between obesity and reproduction, and its actions are mediated by two types of receptors: adiponectin receptor 1 (AdipoR1) and adiponectin receptor 2 (AdipoR2). This study compares the expression levels of adiponectin and adiponectin receptor mRNAs and proteins in selected areas of the porcine hypothalamus responsible for GnRH production and secretion: the mediobasal hypothalamus (MBH), pre‐optic area (POA) and stalk median eminence (SME). The tissue samples were harvested on days 2–3, 10–12, 14–16 and 17–19 of the oestrous cycle. Adiponectin mRNA expression in MBH was significantly lower on days 14–16, whereas in SME, the most pronounced gene expression was found on days 2–3 of the cycle (p < 0.05). Adiponectin protein in MBH was most abundant on days 17–19 and in POA on days 2–3 (p < 0.05). Adiponectin protein expression in SME was at similar level throughout the most of the cycle with a statistically significant drop (p < 0.05) on days 14–16. AdipoR1 gene expression in POA was potentiated on days 2–3 and 10–12 of the oestrous cycle (p < 0.05). In SME, the highest AdipoR1 mRNA expression was noted on days 2–3 (p < 0.05). The concentrations of the AdipoR1 protein in POA were similar throughout the luteal phase (days 2–14 of the cycle), and they decreased on days 17–19 (p < 0.05). In SME, AdipoR1 protein expression peak occurred on days 2–3 (p < 0.05). The expression patterns of the AdipoR2 gene in MBH, POA and SME revealed the highest mRNA levels on days 2–3 of the cycle (p < 0.05). The highest content of AdipoR2 protein in MBH was reported on days 2–3 (p < 0.05), while in POA on days 17–19 and in SME on days 10–12 and 14–16 (p < 0.05). This study demonstrated that adiponectin and adiponectin receptor mRNAs and proteins are present in the porcine hypothalamus and that their expression levels are determined by the pig's endocrine status related to the oestrous cycle.     

Molecular cloning and tissue expression of chicken AdipoR1 and AdipoR2 complementary deoxyribonucleic acids

AdipoR1 and AdipoR2 belong to a novel class of transmembrane receptors that mediate the effects of adiponectin. We have cloned the chicken AdipoR1 and AdipoR2 complementary deoxyribonucleic acids (cDNA) and determined their expression in various tissues. We also investigated the effect of feed deprivation on the expression of AdipoR1 or AdipoR2 mRNA in the chicken diencephalon, liver, anterior pituitary gland, and adipose tissue. The chicken AdipoR1 and AdipoR2 cDNA sequences were 76-83% identical to the respective mammalian sequences. A hydrophobicity analysis of the deduced amino acid sequences of chicken AdipoR1/AdipoR2 revealed seven distinct hydrophobic regions representing seven transmembrane domains. By RT-PCR, we detected AdipoR1 and AdipoR2 mRNA in adipose tissue, liver, anterior pituitary gland, diencephalon, skeletal muscle, kidney, spleen, ovary, and blood. AdipoR1 or AdipoR2 mRNA expression in various tissues was quantified by real-time quantitative PCR, and AdipoR1 mRNA expression was the highest in skeletal muscle, adipose tissue and diencephalon, followed by kidney, ovary, liver, anterior pituitary gland, and spleen. AdipoR2 mRNA expression was the highest in adipose tissue followed by skeletal muscle, liver, ovary, diencephalon, anterior pituitary gland, kidney, and spleen. We also found that a 48 h feed deprivation significantly decreased AdipoR1 mRNA quantity in the chicken pituitary gland, while AdipoR2 mRNA quantity was significantly increased in adipose tissue (P<0.05). We conclude that the AdipoR1 and AdipoR2 genes are ubiquitously expressed in chicken tissues and that their expression is altered by feed deprivation in the anterior pituitary gland and adipose tissue.     

The immediate effects of weaning stress on the hypothalamus‐pituitary‐adrenal alteration of newly weaned piglets

This study was conducted to examine the effects of weaning stress on gene expression of specific markers in hypothalamus‐pituitary‐adrenal (HPA) axis and neuronal activity in the newly weaned piglets. Twelve 28‐days‐old, newly weaned crossbred (Landrace × Yorkshire × Duroc) male piglets from 6 l (2 piglets/l) were randomly categorized into two groups: (a) weaning stress: piglets were separated from their dams, relocated and mixed with the unacquainted domestic piglets for 2 hr (stress, n = 6); (b) no‐stress: piglets stayed with their dams in the farrowing house (NS; n = 6). After weaning stress, all piglets were electrically euthanized and the blood samples/HPA tissues were collected for subsequent analysis, including plasma cortisol and mRNA expression of c‐fos, c‐jun, corticotropin‐releasing hormone (CRH), CRH receptor 1 (CRHR‐1) and adrenocorticotropin hormone receptor (MC2R). Results: Weaning stress significantly (p < 0.05) increased the plasma cortisol level and suppressed the expression of c‐fos and CRH in hypothalamus. In addition, weaning stress enhanced the mRNA abundance of c‐jun and CRHR‐1 in the pituitary gland. No significant differences in the gene expression of MC2R and CRHR‐1 were observed in the adrenal gland between treatment groups. Taken together, HPA involved in weaning stress and CRHR‐1 and c‐jun could be potential markers to evaluate the activation of HPA axis.     

Effect of restricted feeding during the rearing period and a “forced moult” at 40 weeks of production on the productivity of Pekin breeder ducks

1. Six males and 24 female Cherry Valley Pekin ducklings were randomly allocated to each of 12 pens to test the effects of quantitative food restriction during the rearing period on the subsequent reproductive performance. At the end of the laying period (60 weeks) a “forced moult” was introduced and its effect on a further 40 weeks production investigated.

2. The 3 rearing treatments were 50% of ad libitum intake from 3 to 20 weeks; 75% of ad libitum intake from 3 to 20 weeks and ad libitum intake throughout. During the laying period (20–60 weeks) and post forced‐moult period (60–100 weeks) duck breeder pellets were fed ad libitum to all groups.

3. Highly significant (P ≤ 0.01) differences in favour of the restricted groups over the ad libitum‐fed groups were observed in most of the responses studied. The following were the main advantages of food restriction: lower lifetime food intake, lower carcase fat content at 20 weeks, delay in sexual maturity, higher egg production, higher peak and terminal production, higher fertility, higher hatchability of eggs set and lower mortality. Egg mass and hatchability of fertile eggs was not influenced by food restriction in this experiment. The use of a “forced moult” showed that it could be of economical importance.

4. Differences between treatments in respect of absolute and relative visceral masses were also investigated. The absolute masses of the intestine, heart, gizzard and liver all decreased as the degree of food restriction increased. The relative visceral masses showed the opposite trend with the exception of the heart which showed no significant differences between treatments.     

Protein and mRNA expression of follicle‐stimulating hormone receptor and luteinizing hormone receptor during the oestrus in the yak (Bos grunniens)

Follicle‐stimulating hormone (FSH) and luteinizing hormone (LH) have a central role in follicle growth, maturation and oestrus, but no clear pathway in the seasonal oestrus of yak (Bos grunniens) has been found. To better understand the role of FSH and LH in seasonal oestrus in the yak, six yaks were slaughtered while in oestrus, and the pineal gland, hypothalamus, pituitary gland, and gonads were collected. Using real‐time PCR and immunohistochemical assays, we determined the mRNA and protein expression of the FSH and LH receptors (FSHR and LHR) in these organs. The analysis showed that the FSHR mRNA expression level was higher in the pituitary gland tissue compared with LHR (p < .01) during oestrus. By contrast, there was low expression of FSHR and LHR mRNA in the pineal gland and hypothalamus. FSHR mRNA expression was higher than that of LHR (p < .05) in the ovary, whereas LHR mRNA expression was higher than that of FSHR (p < .01) in the uterus. FSHR and LHR proteins were located in the pinealocyte, synaptic ribbon and synaptic spherules of the pineal gland and that FSH and LH interact via nerve fibres. In the hypothalamus, FSHR and LHR proteins were located in the magnocellular neurons and parvocellular neurons. FSHR and LHR proteins were localized in acidophilic cells and basophilic cells in the pituitary gland, and in surface epithelium, stromal cell and gland epithelium in the uterus. In the ovary, FSHR and LHR protein were present in the ovarian follicle. Thus, we concluded that FSHR and LHR are located in the pineal gland, hypothalamus, pituitary and gonad during oestrus in the yak. However, FSHR was mainly expressed in the pituitary gland and ovaries, whereas LHR was mainly expressed in the pituitary gland and uterus.     

The Central Effect of β‐Endorphin and Naloxone on The Biosynthesis of GnRH and GnRH Receptor (GnRHR) in The Hypothalamic‐Pituitary Unit of Follicular‐Phase Ewes

The effects of prolonged, intermittent infusion of β‐endorphin or naloxone into the third cerebral ventricle of follicular‐phase ewes on the expression of genes encoding GnRH and GnRHR in the hypothalamus and GnRHR in the anterior pituitary gland (AP) were examined by an enzyme‐linked immunoabsorbent assay. Activation or blockade of μ‐opioid receptors significantly decreased or increased the GnRH concentration and GnRHR abundance in the hypothalamus, respectively, and affected in the same way GnRHR quantity in the AP gland. The changes in the levels of GnRH and GnRHR after treatment with β‐endorphin as well as following action of naloxone were reflected in fluctuations of plasma LH concentrations. On the basis of these results, it is suggested that β‐endorphinergic system in the hypothalamus of follicular‐phase ewes affects directly or via β‐endorphin‐sensitive interneurons GnRH and GnRHR biosynthesis leading to suppression in secretory activity of the hypothalamic‐pituitary axis.     

Effects of calcium soap of rice bran oil fatty acids supplementation alone and with DL‐α‐tocopherol acetate in lamb diets on performance,digestibility, ruminal parameters and meat quality

Thirty‐six Malpura lambs (28 day old and 6.7 ± 0.25 kg BW) were distributed equally in three groups having six males and six female. They were ad libitum fed individually three different experimental diets containing calcium soap of fatty acids (CA‐FA) at 0 (T₁) and 40 (T₂ and T₃) g/kg concentrate up to six months of age. Animals in T₃ were supplemented additionally with 40 mg DL‐α‐tocopherol acetate/kg of concentrate. The roughage moiety included ad libitum dry Prosopis cineraria and fresh Azadirachata indica leaves. All the lambs were allowed to suckle from their dam up to weaning (90 day of age). Supplementation of Ca‐FA improved weight gain and feed conversion ratio during both pre‐ (28–90 days) and post‐weaning (91–180 days) phases; however, no effect of DL‐α‐tocopherol was observed. Metabolic parameters during post‐weaning phase revealed non‐significant effect on digestibility but improved nitrogen balance in the test groups. The effect on biochemical attributes did not show any significant alteration in ruminal parameters, blood biochemicals and urinary purine derivatives. Carcass traits revealed higher (p < 0.05) dressing yield and loin eye area with Ca‐FA supplementation. The value of thiobarbituric reactive substances for nuggets prepared from frozen carcasses revealed significant (p < 0.05) reduction in T₃ compared to the other dietary groups. Fatty acid profile of adipose tissue revealed higher (p < 0.001) 9‐octadecanoic, 9‐12‐octadecadienoic, polyunsaturated fatty acids (PUFA), higher ratio of PUFA/saturated fatty acids (SFA), ω‐6/ω‐3 and lower SFA in Ca‐FA‐supplemented groups. It is concluded that supplementation of 40 g/kg calcium soap prepared from industrial grade rice bran oil in lamb ration provided additional energy intake, improved N utilization, gain and feed conversion ratio besides improving dressing yield and meat quality with CLA enriched fatty acid profile. DL‐α‐tocopherol acetate when supplemented at 40 mg/kg feed reduced lipid oxidation of meat products thus improving its keeping quality.     

Effect of humic acids on intestinal viscosity,leaky gut and ammonia excretion in a 24 hr feed restriction model to induce intestinal permeability in broiler chickens

The purpose of this study was to evaluate the effect of humic acids (HA) on intestinal viscosity, leaky gut and ammonia excretion in a 24 hr feed restriction (FR) model to induce intestinal permeability in chickens. One‐day‐old male Cobb‐Vantress broilers were randomly allocated to one of two groups (n = 25 chickens), with or without 0.2% of isolated HA from worm‐compost, and placed in brooder batteries. Chicks had ad libitum access to water and feed for 14 days. Intestinal permeability was induced by 24 hr FR starting at 14 days. At 15 days of age, chickens in both groups were given an appropriate dose of fluorescein isothiocyanate dextran (FITC‐d) by oral gavage. Intestine and liver samples were also collected to evaluate viscosity and bacterial translocation (BT), respectively. An increase (p < .05) in intestinal viscosity was observed in the experimental group consuming 0.2% of HA and was confirmed in a published in vitro digestion model that simulates the chemical and physical conditions of the crop, proventriculus and intestine of chickens. Furthermore, the treated group also showed a significant reduction in FITC‐d, liver BT and ammonia in the manure. These results suggest that HA have a positive impact in intestinal integrity in chickens.     

Role of body weight and food intake after photostimulation on ovarian function at first egg in broiler breeder females

1. The role of body weight during rearing and food allocation after photostimulation on ovarian function in broiler breeder females was examined in two experiments. In experiment 1 birds were fed ad libitum, or to grow to 0.7 or 0.4 of ad libitum‐fed body weight at 20 weeks of age. After photostimulation at 16, 19 and 22 weeks respectively they were fed ad libitum, 145 g/d or 115 g/d in a factorial design. The ovary of each bird was examined after it had laid an egg. In experiment 2, restricted birds (0.4 of ad libitum‐fed body weight) were fed 125 g/d after laying an egg or ad libitum and a third group were given 125 g/d for 3 to 4 weeks and then fed ad libitum. The ovaries of these birds were examined 6 to 7 weeks after their first egg.

2. Food restriction after photostimulation had little effect on ovarian function in birds fed ad libitum during rearing. These birds had 2 to 3 hierarchies of yellow follicles of similar size. Restricted birds fed ad libitum after photostimulation had a large increase in the numbers of yellow follicles (1.7 to 2.0 hierarchies) compared with birds fed 145 g/d or 115 g/d which had 1.2 to 1.6 hierarchies of yellow follicles.

3. Age at first egg was largely a function of rearing treatment but feeding 115 g/d to the 0.4 treatment birds delayed the onset of lay compared with the other treatments.

4. Ad libitum feeding in restricted birds after the onset of lay resulted in a similar increase in the number of yellow follicles as the response to ad libitum feeding after photostimulation.

5. The prevalence of birds with atretic follicles was relatively high in birds fed ad libitum during rearing and in restricted birds fed ad libitum after photostimulation.

6. Yolk weight increased with age at photostimulation and food restriction decreased yolk weight by about 1 g compared with ad libitum feeding after photostimulation.