Endogenous ileal losses of nitrogen and amino acids in pigs and piglets fed graded levels of casein

In order to determine ileal losses of nitrogen (N) and amino acids (AA) and the coefficients of apparent and true ileal digestibility (AID, TID) of N and AA from casein in piglets and pigs, two experiments were conducted. In Experiment 1, 24 piglets were used. The piglets were weaned at 17 days of age, weighing 6.4 kg and cannulated at terminal ileum. Ileal digesta was collected at 28-29 and 35-36 days of age in period 1 and 2, respectively. Feed intake was 150 and 300 g x d(-1) during the first and second period. In Experiment 2, 16 castrates weighing 52.5 kg and cannulated at terminal ileum were used. The intake level of digestible energy was 2.5 times their maintenance requirement. The experiment lasted 7 days and ileal digesta was collected on day 6-7. Treatments consisted of four levels of N from casein: 8, 16, 24 and 32 g N x kg(-1) feed, respectively. Results showed that N level did not increase N or AA ileal losses. In piglets, N and AA ileal losses were similar between periods, except for period 2, where losses per kg DMI were about 47 and 64% higher for glycine and proline, respectively (p < 0.05). When ileal losses from pigs and piglets were compared, piglets had higher (p < 0.05) ileal losses of N and AA (excepted glutamic acid and alanine). A lower (p < 0.05) AID was observed in piglets in period 2 for N, methionine, glutamic acid, glycine and proline. With exception of glycine in pigs, all values for TID of N and AA of casein were superior to 0.90. Piglets had higher TID of N, leucine, isoleucine, valine and phenylalanine. These results showed that piglets have higher ileal losses than pigs.     

Interleukin-1 beta-induced anorexia is reversed by ghrelin

Interleukins, in particular interleukin-1β (IL-1β), reduce food intake after peripheral and central administration, which suggests that they contribute to anorexia during various infectious, neoplastic, and autoimmune diseases. On the other hand, ghrelin stimulates food intake by acting on the central nervous system (CNS) and is considered an important regulator of food intake in both rodents and humans. In the present study, we investigated if ghrelin could reverse IL-1β-induced anorexia. Intracerebroventricular (i.c.v.) injection of 15, 30 or 45 ng/μl of IL-1β caused significant suppression of food intake in 20 h fasting animals. This effect lasted for a 24 h period. Ghrelin (0.15 nmol or 1.5 nmol/μl) produced a significant increase in cumulative food intake in normally fed animals. However, it did not alter food intake in 20 h fasting animals. Central administration of ghrelin reduced the anorexic effect of IL-1β (15 ng/μl). The effect was observed 30 min after injection and lasted for the next 24 h. This study provides evidence that ghrelin is an orexigenic peptide capable of antagonizing IL-1β-induced anorexia.     

Endogenous ileal losses of nitrogen and amino acids in pigs and piglets fed graded levels of casein

Abstract

In order to determine ileal losses of nitrogen (N) and amino acids (AA) and the coefficients of apparent and true ileal digestibility (AID, TID) of N and AA from casein in piglets and pigs, two experiments were conducted. In Experiment 1, 24 piglets were used. The piglets were weaned at 17 days of age, weighing 6.4 kg and cannulated at terminal ileum. Ileal digesta was collected at 28 – 29 and 35 – 36 days of age in period 1 and 2, respectively. Feed intake was 150 and 300 g · d^?1 during the first and second period. In Experiment 2, 16 castrates weighing 52.5 kg and cannulated at terminal ileum were used. The intake level of digestible energy was 2.5 times their maintenance requirement. The experiment lasted 7 days and ileal digesta was collected on day 6 – 7. Treatments consisted of four levels of N from casein: 8, 16, 24 and 32 g N · kg^?1 feed, respectively. Results showed that N level did not increase N or AA ileal losses. In piglets, N and AA ileal losses were similar between periods, except for period 2, where losses per kg DMI were about 47 and 64% higher for glycine and proline, respectively (p < 0.05). When ileal losses from pigs and piglets were compared, piglets had higher (p < 0.05) ileal losses of N and AA (excepted glutamic acid and alanine). A lower (p < 0.05) AID was observed in piglets in period 2 for N, methionine, glutamic acid, glycine and proline. With exception of glycine in pigs, all values for TID of N and AA of casein were superior to 0.90. Piglets had higher TID of N, leucine, isoleucine, valine and phenylalanine. These results showed that piglets have higher ileal losses than pigs.     

Effects of neuropeptide Y on food intake and brain biogenic amines in the rainbow trout (Oncorhynchus mykiss)

Neuropeptide Y (NPY) is one of the most potent stimulants of food intake in mammals, but very little is known about NPY actions in fish. The present study investigated the role of NPY in food intake in the rainbow trout (Oncorhynchus mykiss). Food intake was monitored at different times after intracerebroventricular administration of porcine NPY (4 or 8 microg). Both doses significantly increased food intake at 2 and 3 h, and this effect was dose-dependent. However, 50 h after administration of NPY, food intake was significantly lower than in control fish, and cumulative food intake had returned to levels similar to those seen in the control group. The NPY antagonist (D-Tyr27,36, D-Thr32)-NPY (10 microg) inhibited food intake 2 h after icv administration, but did not block the orexigenic effect of NPY when administered jointly with 4 microg NPY. To identify the NPY receptor subtypes involved in the effects of NPY on food intake, we studied the effects of the Y1 receptor agonist (Leu31, Pro34)-NPY (4 microg), the Y2 receptor agonist NPY(3-36) (4 microg), and the highly specific Y5 receptor agonist (cPP(1-7), NPY19-23, Ala31, Aib32, Gln34)-hPP (4 microg). Short-term (2 h) food intake was moderately stimulated by the Y1 agonist, more strongly stimulated by the Y2 agonist, and unaffected by the Y5 agonist. We found that administration of NPY (8 microg icv) had no effect on aminergic systems in several brain regions 2 and 50 h after NPY administration. These results indicate that NPY stimulates feeding in the rainbow trout, and suggest that this effect is cooperatively mediated by Y2- and Y1-like NPY receptors, not by Y5-like receptors.     

Sex-specific effects of prolactin on food intake by rats

While prolactin (PRL) has been reported to increase food intake by virgin female rats, its effects on food intake by male rats are relatively unexplored. The present studies examined the possibility that PRL has sex-specific effects on food intake by rats. In the first study, intact female and male rats were given subcutaneous injections of saline vehicle or ovine (o) PRL (1.0 mg/kg) twice daily at 08:00 and 20:00 h for 10 days. Food intake, body weight, and water intake were measured daily. Results indicate that oPRL administration increased food intake by an average of 4.5 g per day in female subjects, but did not significantly alter body weight or water intake. Male rats treated with oPRL did not significantly alter their food intake, even after an additional five days of treatment. In the second study, a wide range of oPRL doses (vehicle, 0.02, 0.2, 2.0, and 20.0 mg/kg/day) were tested in gonadectomized female and male rats. The results indicate that female rats responded to increasingly larger doses of oPRL with greater increases in food intake, with a maximum increase of approximately 6. 1 g per day at a dose of 20.0 mg/kg. In contrast, male rats maintained baseline levels of intake across all oPRL doses tested. These data suggest that PRL has sex-specific effects on food intake.     

Effect of ketamine anesthesia on daily food intake in Macaca mulatta and Cercopithecus aethiops

Ketamine hydrochloride is frequently administered to non-human primates as a means of chemical restraint. This procedure can be a frequent source of stress to monkeys at research facilities, impacting animal health, well-being and research quality. This study was designed to measure ketamine's effect on daily food intake, a parameter that reflects and influences animal well-being and directly impacts research studies. On five occasions, baseline daily food intake was compared to daily food intake occurring 24, 48, 72, 96, and 120 h after an intramuscular injection of 10 mg/kg ketamine in male African green monkeys (AGMs) (Cercopithecus aethiops) and male and female rhesus macaques (Macaca mulatta). AGMs and female rhesus macaques had significantly reduced daily food intake during the first 4 days after receiving ketamine. The AGMs continued to display significantly reduced daily food intake on the fifth day after ketamine. The male rhesus macagues showed a trend toward reduced daily food intake, greatest during the first 2 days and remaining less than baseline intake through the fifth day following ketamine. The degree of observed food intake reduction was most severe at the 24 h (mean percent intake reduction: AGMs: 57%; rhesus males: 48%; rhesus females: 40%) and 48 h time points (AGMs: 24%; rhesus males: 14%; rhesus females: 13%). A subset of the AGMs that did not receive ketamine, but observed other animals in the room receive ketamine, showed reduced food intake at 24 and 48 h after ketamine, though not to the degree associated with ketamine administration. These results indicate that ketamine anesthesia is associated with a prolonged reduction in daily food intake in AGMs and rhesus macaques. Frequent use of ketamine in non-human primates may have a significant impact on animal health and well-being, and alternatives to its use warrant consideration.     

Co-administration of dopamine D1 and D2 agonists additively decreases daily food intake, body weight and hypothalamic neuropeptide Y level in rats

This study investigated whether co-administration of dopamine D1 and D2 agonists might additively inhibit the feeding effect and whether this effect was mediated by the action on hypothalamic neuropeptide Y (NPY). The D1 agonist SKF 38393 (SKF) and D2 agonists apomorphine (APO) or quinpirole (QNP) were administered, alone or in combination, to examine this possibility. In single administration, decreases of daily food intake were observed only in rats treated twice a day with a higher dose of SKF, APO or QNP. However, combined administration of D1 and D2 agonists, with each agent at a dose that alone did not induce anorexia in one daily treatment, exerted a significant effect. These results reveal that co-activation of D1 and D2 receptors can additively reduce daily food intake and body weight. The same treatment also decreased the level of hypothalamic NPY 24 h post-treatment. These results suggest an additive effect during combined activation of D1 and D2 receptor subtypes to decrease food intake and body weight that are mediated by the action of hypothalamic NPY. Similar to the effects seen in healthy rats, combined D1/D2 administration was also effective in the reduction of food intake in diabetic rats, revealing the efficiency of D1/D2 agonist in the improvement of hyperphasia in diabetic animals.     

Effects of oral supplementation with Spirulina and Chlorella on growth and digestive health in piglets around weaning

Weaning of piglets is associated with important changes in gut structure and function resulting from stressful events such as separation from the sow, moving to a new facility and dietary transition from a liquid to a solid feed. This may result in post-weaning diarrhoea and a decrease in feed intake and growth. In humans, the cyanobacterium Spirulina platensis (SP) and the freshwater microalga Chlorella vulgaris (CV) are known for their beneficial health effects. This study aimed to determine the effects of early oral administration of Spirulina and Chlorella in piglets on mucosal architecture and cytokine expression in the intestine around weaning, and consequences on growth performance and diarrhoea incidence. The experiment was conducted on 108 suckling piglets of 14 days of age (initial BW=4.9±0.7 kg) and weaned at 28 days of age (day 0). Animals received orally 385 mg/kg BW per day of SP or CV, or water (negative control (NC)) during 4 weeks from day −14 to day 14 and their growth performance was measured daily. After weaning, growth, feed intake and diarrhoea incidence were measured daily. Intestinal morphology and functionality were assessed at day −1, day 2, and day 14. During the suckling period, average daily gain (ADG) in SP piglets was higher, resulting in a higher weaning BW compared to NC and CV piglets (P<0.05). No significant difference between treatments was observed for ADG, average daily feed intake, and gain to feed (G : F) ratio after weaning, but the extent of growth retardation after weaning was the lowest in piglets supplemented with Chlorella (P<0.01). Supplementation with Spirulina reduced diarrhoea incidence by 50% from day 0 to day 14 (P<0.05). Mucosal architecture at the jejunum was unaffected by Spirulina or Chlorella administration (P>0.10). Shorter ileal villi were measured in SP and CV piglets than in NC piglets (P<0.05). Cytokine expression did not differ between treatments in response to weaning. At day 14, IL-8 expression in the ileum was higher in SP piglets, while IL-1β expression in the jejunum was higher in CV piglets (P<0.05). This study shows that Spirulina administration around weaning alleviates diarrhoea in weaned piglets, without marked modulation of local inflammation.     

Does the newly weaned piglet select a zinc oxide supplemented feed,when given the choice?

An experiment was conducted to examine whether weaned piglets would display preference for a food containing a pharmacological level of zinc oxide (ZnO). A total of 60 piglets were weaned at 7.8 kg ± 0.14 (s.e.m.) and 27.8 ± 0.11 days of age into eight mixed sex groups of seven or eight piglets per pen. Groups were balanced for litter origin, weaning weight and sex. Piglet feeding behaviour was constantly recorded by a multi-spaced feeding behaviour recording system (Leeds University Feeding Behaviour System) in each pen. Each pen of pigs was offered ad libitum access to two different foods (16.2 MJ digestible energy, 16 g lysine/kg), which differed only in the level of ZnO supplementation: unsupplemented (U) or supplemented (Z; ZnO 3100 mg/kg). Both foods contained a basal level of zinc (100 mg/kg). Feeding time was recorded for each individual at each trough. Piglets were weighed at weaning and at 7 and 13 days thereafter. The experiment ran for 13 days. Any piglet observed with post-weaning scour (Y) was recorded and treated appropriately whereas healthy piglets were categorised as N (no scour). Preference for a food was defined as being significantly different from 50% of total feed intake or time spent feeding. There was no difference between piglet numbers selecting each food as their first meal. However, within the first 24 h, piglets preferred (P < 0.001) food U, spending only 36.3% (32.2 to 40.5; 95% confidence interval) of feeding time at food Z. Throughout the experiment, piglets showed aversion (P < 0.001) to food Z, consumption being 8.9% (5.1 to 13.6) and 15.7% (8.9 to 23.9) of total intake in weeks 1 and 2, respectively. Individual piglets showed their preference for food U with only 16.6% (14.6 to 18.5) and 21.8% (19.6 to 24.0) of feeding time spent on food Z in weeks 1 and 2, respectively. Scouring piglets did not show any difference in feeding behaviour from healthy piglets in either week. Average piglet gain (of all piglets) was low, at 0.039 ± 0.03 and 0.272 ± 0.04 kg/day in weeks 1 and 2, respectively. Given a choice, weaned piglets showed a clear preference for the food U even when exhibiting post-weaning scour. It can be concluded that the newly weaned, naïve, piglet is not able to recognise a food with clear health and performance benefits but selected the food U due to the reduced palatability of the food Z.     

Effect of allopregnanolone on d-[3H]-aspartate release and [3H]-glutamate uptake in the hippocampus of kainate-treated mice.

In order to determine whether the status epilepticus leads to alterations in the neurosteroid effect on excitatory amino acid transmission, we studied the influence of allopregnanolone on aspartate release and glutamate uptake in mouse hippocampus at various times after kainate administration. No significant differences in the K+-stimulated D-[3H]-aspartate release from the hippocampi of saline- and kainate-treated mice were observed; however, that parameter tended to fall in tissues collected I h after kainate administration. Allopregnanolone significantly attenuated the K+-stimulated D-[3H]-aspartate release from the hippocampi of control animals, as well at 24 h and 7 days after kainate injection; in contrast it did not affect amino acid release from the hippocampi collected 1 h after kainate administration. Kainate administration had no effect on [3H]-glutamate uptake after 1 and 24 h, but elevated that parameter on day 7. Allopregnanolone (10 and 100 microM) did not affect [3H]-glutamate uptake in control and kainate-treated mice. In conclusion, the present study indicates a loss of the inhibitory effect of allopregnanolone on the potasium-stimulated D-[3H]-aspartate release from mouse hippocampus during the kainate-induced status epilepticus; moreover, it excludes involvement of this neurosteroid in the regulation of hippocampal [3H]-glutamate uptake in both control and kainate-treated mice.     

The effects of adrenergic, opioid and pancreatic polypeptidergic compounds on feeding and other behaviors in neonatal leghorn chicks

The present study examined the effects of intracerebral (IC) administration of pancreatic polypeptide (PP), neuropeptide Y (NPY), norepinephrine (NE), dynorphin and naloxone on food intake in 2-day-old Leghorn chicks. Of the compounds studied, only PP (20 micrograms) and naloxone (10 and 20 micrograms) elevated food intake significantly as compared to saline injections. NPY, a potent orexigenic agent in mammals, did not elevate consumption significantly in a dose-related fashion. This latter finding was attributed to the occurrence of tonic-clonic convulsions following NPY administration. However, for those chicks which did not exhibit behavioral convulsions, food intake appeared to be elevated by 1, 5 and 10 micrograms of NPY. Similarly, NE did not elevate food intake but instead induced sedation and narcolepsy, a behavioral response which could be distinguished from the convulsions observed after NPY. In a separate group of chicks, the effect of NPY on cortical activity was examined. Bipolar electrodes were used to record EEG activity before and after IC injections of saline, NPY or NE. The behavioral convulsions induced by NPY corresponded with an increase in high amplitude sharp-wave activity, which persisted for up to 30 min post-injection. Collectively, these results suggest that the neurochemical substrates for feeding in 2-day-old Leghorn chicks are distinct from those underlying food intake in adult mammals.     

The effect of administration of estradiol and testosterone on body growth of young male rats.

The influence of estradiol and testosterone on body growth of young male Wistar rats was investigated. In the first experiment, estradiol was given to intact ad libitum fed male rats at 32, 37 and 42 days of age. Moreover, two untreated groups of animals were used: one was fed restrictedly according to the food intake of animals receiving estradiol and another was fed ad libitum. The animals were sacrificed at 47 days of age. Both untreated groups of animals achieved significantly higher body weight and length of tibia than estradiol treated animals. Also the growth of the tail of untreated animals was more intensive than that of estradiol treated animals. In the second experiment, estradiol was given to intact ad libitum fed male rats at 30, 35 and 45 days of age. Moreover, testosterone was given to a half of these animals at 45, 50 and 55 days of age. The animals were sacrificed at 60 days of age. Administration of testosterone significantly increased the growth of the tail and tibia in comparison to the animals which did not receive testosterone after estradiol administration. The results of the present study show that the inhibitory effect of estradiol on body growth of young male rats is not only the result of decreased food intake and that testosterone can improve the skeletal growth of male rats altered by previously given estradiol.     

Effect of inflammation stimulation on energy and nutrient utilization in piglets selected for low and high residual feed intake

Selection of animals for improved feed efficiency can affect sustainability of animal production because the most efficient animals may face difficulties coping with challenges. The objective of this study was to determine the effects of an inflammatory challenge (using an intravenous injection of complete Freund’s adjuvant – CFA) in piglets from two lines of pigs divergently selected during the fattening period for a low (RFI−) or a high (RFI+) residual feed intake (RFI; difference between actual feed intake and theoretical feed requirements). Nitrogen and energy balances (including heat production – HP – and its components: activity-related HP – AHP, thermic effect of feeding, and resting HP) were measured individually in thirteen 20-kg BW castrated male piglets (six and seven from RFI+ and RFI− line, respectively) fed at the same level (1.72 MJ ME/kg BW^0.60 per day) from 3 days before to 3 days after CFA injection. Dynamics of dietary U-¹³C-glucose oxidation were estimated from measurements of ¹³CO₂ production on the day before and 3 days after the CFA injection. Oxidation of dietary nutrients and lipogenesis were calculated based on HP and O₂ consumption and CO₂ production. The data were analyzed as repeated measurements within piglets in a mixed model. Before CFA injection, RFI− piglets had a lower resting energy expenditure than RFI+ piglets, which tended to increase energy retention because of a higher energy retention as fat. The CFA injection did not affect feed intake from the day following CFA injection onwards but it increased energy retention (P=0.04). Time to recover 50% of ¹³C from dietary glucose as expired ¹³CO₂ was higher in RFI+ piglets before inducing inflammation but decreased after to the level of RFI− piglets (P<0.01). Oxidation of U-¹³C-glucose tended to slightly increased in RFI− piglets and to decreased in RFI+ piglets (P=0.10) because of CFA. Additionally, RFI− piglets had a lower respiratory quotient during the 1st day following the CFA injection whereas RFI+ piglets tended to have a higher respiratory quotient. In conclusion, selection for RFI during the fattening period also affected the energy metabolism of pigs during earlier stages of growth. The effects of CFA injection were moderated in both lines but the most efficient animals (RFI−) exhibited a marked re-orientation of nutrients only during the 1st day after CFA, and seemed to recover thereafter, whereas the less efficient piglets expressed a more prolonged alteration of their metabolism.     

Dietary supplementation with <Emphasis Type="Italic">Astragalus</Emphasis> polysaccharide enhances ileal digestibilities and serum concentrations of amino acids in early weaned piglets

Two experiments were conducted to evaluate the effects of dietary supplementation with Astragalus polysaccharide (APS) on growth performance, apparent ileal digestibilities (AID) of amino acids (AA), and their serum concentrations in early weaned piglets. In Exp. 1, 60 pigs were weaned at 21 days of age (BW 7.35 ± 0.23 kg) and allocated to three treatments (20 pigs/treatment), representing supplementing 0.0% (control), 0.02% colistin (antibiotic), or 0.1% APS to a corn- and soybean meal-based diet. Average daily gain (ADG), average daily feed intake (ADFI), and feed/gain ratio (F/G) were measured weekly. Blood samples were obtained from five pigs selected randomly from each treatment for the measurement of serum free AA concentrations on days 7, 14, and 28. In Exp. 2, 12 pigs were weaned at 21 day of age (BW 7.64 ± 0.71 kg), assigned to three treatment groups as in Exp. 1, and surgically fitted with a simple T-cannula at the terminal ileum. Ileal digesta samples were obtained for the measurement of AID of AA on days 7, 14 and 28. Dietary APS did not affect ADFI, but enhanced (P < 0.05) ADG by 11 and 4.4%, and improved F/G by 5.6 and 8.4%, respectively, compared with the control and antibiotic groups. Addition of APS to the diet increased AID and serum concentrations of most nutritionally essential and non-essential AA (including arginine, proline, glutamate, lysine, methionine, tryptophan, and threonine) on days 14 and 28. Circulating levels of total AA were affected by the age of pigs and treatment × time interaction. Collectively, these findings indicate that APS may ameliorate the digestive and absorptive function and regulate AA metabolism to beneficially increase the entry of dietary AA into the systemic circulation, which provide a mechanism to explain the growth-promoting effect of APS in early weaned piglets.     

Influence of thermal and nutritional acclimatization on body temperatures and metabolic rate

1. An investigation of the influence of previous thermal and nutritional experience on body temperatures and metabolic rate has been carried out with growing piglets. Littermates were kept, from shortly after birth, at either 10 or 35 degrees C and fed either a high (H) or a low (L) energy intake. At 8 weeks of age the animals were exposed to a series of environmental temperatures of 10, 20, 27 and 35 degrees C for 1.5 hr and their rates of oxygen consumption were determined over the last 45 min. At the end of the session body temperatures were measured. 2. Rectal temperatures measured 24 hr after the start of the last meal were higher at each test temperature in piglets which had been living at 35 degrees C than in those at 10 degrees C. Also, rectal temperatures were higher in those on the H intake for animals which had been living in either the hot or the cold environment. 3. Skin temperature on the back was similar in all groups at any given test temperature although there was a tendency for those on an H intake to have the higher temperatures. Skin temperatures of the legs and ears were higher in the 10H and 10L groups than in the 35H or 35L groups at all the test environmental temperatures; energy intake had little effect. 4. Metabolic rate was greater for the animals on the H than the L intake, for those which had been living at either 10 or 35 degrees C at all the test environmental temperatures. The analysis did not reveal any significant difference related to the overall effect of living temperature, which was independent of energy intake. 5. At thermal neutrality (27 degrees C) there was a significant interaction, between energy intake and normal living temperature, on metabolic rate. Living temperature was found to modify the effect of intake: the difference between the two intakes was greater in those from the cold environment than from the hot.     

Neuropeptide Y effect on food intake in broiler and layer chicks

Broiler chicks eat more food than layer chicks. In this study, we examined the involvement of orexigenic peptide neuropeptide Y (NPY) in the difference in food intake between broiler and layer chicks (Gallus gallus). First, we compared the hypothalamic mRNA levels of NPY and its receptors (Y1 and Y5 receptors) between these strains at 1, 2, 4, and 8 days of age. Daily food intake was significantly higher in broiler chicks than layer chicks after 2 days of age. However, the hypothalamic NPY mRNA level was significantly lower in broiler chicks than layer chicks except at 8 days of age. In addition, the mRNA levels of NPY receptors were also significantly lower in broiler chicks than layer chicks at 2 and 4 days of age (Y1 receptor) or 2 days of age (Y5 receptor). These results suggest that the differences in the expressions of hypothalamic NPY and its receptors do not cause the increase in food intake in broiler chicks. To compare the orexigenic effect of NPY between broiler and layer chicks, we next examined the effects of central administration of NPY on food intake in these strains. In both strains, central administration of NPY significantly increased food intake at 2, 4 and 8 days of age. All our findings demonstrated that the increase in food intake in broiler chicks is not accompanied with the over-expression of NPY or its receptor.     

Alpha-melanocyte stimulating hormone plays an important role in the regulation of food intake by the central melanocortin system in chicks

Proopiomelanocortin (POMC, a precursor of melanocortin peptides) neurons in the hypothalamus play an important role in the central regulation of food intake in mammals. There is evidence that human melanocortin peptides alpha-, beta- and gamma2-melanocyte-stimulating hormone (α-, β- and γ2-MSH) significantly decreased food intake in chickens. However, the amino acid sequences of β- and γ2-MSH of chickens are different from those of humans whereas the amino acid sequence of α-MSH is conserved between these species. In the present study, we examined the effects of the central administration of α-, chicken β-, and chicken γ2-MSH on food intake in chicks. Central administration of α-MSH significantly suppressed food intake in chicks. In contrast, β- and γ2-MSH did not influence food intake in chicks. Central administration of HS014, a melanocortin 4 receptor antagonist, significantly reversed the anorexigenic action of α-MSH, suggesting that this action is mediated by the melanocortin 4 receptor in chicks as well as in mammals. These results suggest that α-MSH may play an important role in the regulation of food intake by the central melanocortin system in chicks.     

New insights on the management of wildlife diseases using multi-state recapture models: the case of classical swine fever in wild boar

Background

The understanding of host-parasite systems in wildlife is of increasing interest in relation to the risk of emerging diseases in livestock and humans. In this respect, many efforts have been dedicated to controlling classical swine fever (CSF) in the European Wild Boar. But CSF eradication has not always been achieved even though vaccination has been implemented at a large-scale. Piglets have been assumed to be the main cause of CSF persistence in the wild since they appeared to be more often infected and less often immune than older animals. However, this assumption emerged from laboratory trials or cross-sectional surveys based on the hunting bags.

Methodology/Principal Findings

In the present paper we conducted a capture-mark-recapture study in free-ranging wild boar piglets that experienced both CSF infection and vaccination under natural conditions. We used multi-state capture recapture models to estimate the immunization and infection rates, and their variations according to the periods with or without vaccination. According to the model prediction, 80% of the infected piglets did not survive more than two weeks, while the other 20% quickly recovered. The probability of becoming immune did not increase significantly during the summer vaccination sessions, and the proportion of immune piglets was not higher after the autumn vaccination.

Conclusions/Significance

Given the high lethality of CSF in piglets highlighted in our study, we consider unlikely that piglets could maintain the chain of CSF virus transmission. Our study also revealed the low efficacy of vaccination in piglets in summer and autumn, possibly due to the low palatability of baits to that age class, but also to the competition between baits and alternative food sources. Based on this new information, we discuss the prospects for the improvement of CSF control and the interest of the capture-recapture approach for improving the understanding of wildlife diseases.     

Effects of excess biotin administration on the growth and urinary excretion of water-soluble vitamins in young rats

To determine the effects of excess biotin administration on growth and water-soluble vitamin metabolism, weaning rats were fed on a 20% casein diet containing 0.00002% biotin, or same diet with 0.04, 0.08, 0.10, 0.20, 0.50, 0.80 or 1.0% added biotin for 28 days. More than 0.08% biotin administration decreased the food intake and body weight gain compared with the levels in control rats. An accumulation of biotin in such tissues as the liver, brain and kidney increased in a dose-dependent manner, and the both bound and free biotin contents in the liver also increased in a dose-dependent manner. An excess administration of biotin did not affect the urinary excretion of other water-soluble vitamins, suggesting no effect on the metabolism of other water-soluble vitamins. The results of the food intake and body weight gain indicated that the lowest observed adverse effect level for young rats was 79.2 mg/kg body weight/day, while the no observed adverse effect level was 38.4 mg/kg/day. These results suggested immediately setting a tolerable upper intake level for biotin.     

No effect of the plant growth regulator, chlormequat, on boar fertility

Chlormequat is a commonly used plant growth regulator in agriculture. Defined levels of chlormequat residue are allowed in food and an acceptable daily intake is defined for humans. However, there are results in the literature suggesting that a daily intake below the acceptable level for human is detrimental for mammalian reproduction. In the present experiment we investigated the effect of chlormequat at levels up to that acceptable for humans on reproduction in male pigs. Chlormequat (also known as chlorocholine chloride (CCC)) was mixed into the diet and given to the experimental animals at three levels (three treatment groups), i.e. 0 mg CCC/kg BW per day (Control), 0.025 mg CCC/kg BW per day and 0.05 mg CCC/kg BW per day. Eight mother sows per treatment group were used in the experiment. From the day of insemination, the mother sows received the experimental diets. The piglets were weaned at 4 weeks of age and two boar littermates continued on the same treatment as the dam until maturity and delivery of semen for in vitro fertilization (IVF) and in vivo fertilization. Semen volume, sperm concentration and fraction of live sperms were not (P 0.46) detrimentally affected by chlormequat intake. The fraction of oocytes developing to more than the one-cell stage at day 5 after IVF was not (P = 0.88) detrimentally affected by chlormequat intake. Chlormequat intake did not detrimentally affect the fraction of gilts being pregnant after one insemination (P = 0.65) or the number of embryos in the pregnant gilts (P = 0.36). Serum chlormequat concentration was 0.9 μg/kg in the 0.025 mg CCC/kg BW per day group and 1.8 μg/kg in the 0.05 mg CCC/kg BW per day group, but was below the detection limit in control animals. In conclusion, the plant growth regulator chlormequat could not be proven to be detrimental to the selected reproduction traits in male pigs. This is in contrast to existing results from the male mouse.