Depressed Intake Research Articles

Can sunbleak Leucaspius delineatus or topmouth gudgeon Pseudorasbora parva disperse through saline waters?

In order to determine the potential for the invasive fishes sunbleak Leucaspius delineatus and topmouth gudgeon Pseudorasbora parva to disperse through saline waters their behaviour and physiology were investigated during exposure to salinities of 10·0 and 12·5. Increased salinity caused an increase in whole body cortisol in both species, but sunbleak and topmouth gudgeon showed very different metabolic and behavioural responses to the salinity stress. Sunbleak displayed increased swimming activity in brackish water, which may be important for dispersal through saline waters in the wild, although there were increased metabolic costs associated with this behaviour. Conversely, topmouth gudgeon showed a reduction in both swimming activity and metabolic rate in brackish waters. A pronounced depression in food intake (70–80%) was shown by both species during the salinity exposures. Both sunbleak and topmouth gudgeon, however, showed a full recovery of food intake within 24 h following return to fresh water. Despite the fact that exposure to saline waters is stressful, and affects both physiology and behaviour, rapid recovery of appetite after return to fresh water suggests that short‐term use of brackish waters is a feasible dispersal route for sunbleak and topmouth gudgeon in the wild.

Depression in Feed Intake by a Highly Fermentable Diet Is Related to Plasma Insulin Concentration and Insulin Response to Glucose Infusion

The effects of dietary starch fermentability on feed intake and nutrient digestibility were evaluated in a crossover study, which was also designed to find factors that predict individual variation in feed intake response to starch fermentability. Thirty-two multiparous Holstein cows (121±48 d in milk, 44±7 kg/d of milk yield; mean±SD) were randomly assigned to treatment sequence and were fed a diet intermediate to the treatments during a preliminary 28-d period. Treatments were dry ground corn grain and high-moisture corn harvested from the same field. Treatment periods were 14 d, with the final 4 d used for data and sample collection. Diets included corn silage and alfalfa haylage at a 2:1 ratio and were 26% neutral detergent fiber, 17% crude protein, 32% starch, and 3.5% fatty acids. High-moisture corn decreased dry matter intake (DMI) by 8%, but did not significantly alter digestible DMI. Individual DMI responses were highly variable, and variables from preliminary plasma analyses, propionate challenge tests, glucose tolerance tests, and hepatic mRNA analysis were assessed as potential predictors of DMI response to increased dietary starch fermentability. Of the covariates tested, only preliminary plasma insulin concentration and insulin response to glucose infusion were significant predictors of DMI response. High preliminary plasma insulin concentration was correlated with greater depression in DMI with increased fermentability; conversely, greater insulin secretion in response to glucose infusion was associated with minimal depression in DMI. These insulin variables were not significantly correlated. Consistent with past results, increased dietary starch fermentability decreased DMI. Significant correlations between insulin variables and individual DMI responses may warrant further investigation.

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Effect of thermal stress on physiological parameters, feed intake and plasma thyroid hormones concentration in Alentejana, Mertolenga, Frisian and Limousine cattle breeds

The aim of the present study was to assess the heat tolerance of animals of two Portuguese (Alentejana and Mertolenga) and two exotic (Frisian and Limousine) cattle breeds, through the monitoring of physiological acclimatization reactions in different thermal situations characterized by alternate periods of thermoneutrality and heat stress simulated in climatic chambers. In the experiment, six heifers of the Alentejana, Frisian and Mertolenga breeds and four heifers of the Limousine breed were used. The increase in chamber temperatures had different consequences on the animals of each breed. When submitted to heat stress, the Frisian animals developed high thermal polypnea (more than 105 breath movements per minute), which did not prevent an increase in the rectal temperature (from 38.7 degrees C to 40.0 degrees C). However, only a slight depression in food intake and in blood thyroid hormone concentrations was observed under thermal stressful conditions. Under the thermal stressful conditions, Limousine animals decreased food intake by 11.4% and blood triiodothyronine (T3) hormone concentration decreased to 76% of the level observed in thermoneutral conditions. Alentejana animals had similar reactions. The Mertolenga cattle exhibited the highest capacity for maintaining homeothermy: under heat stressful conditions, the mean thermal polypnea increased twofold, but mean rectal temperature did not increase. Mean food intake decreased by only 2% and mean T3 blood concentration was lowered to 85,6% of the concentration observed under thermoneutral conditions. These results lead to the conclusion that the Frisian animals had more difficulty in tolerating high temperatures, the Limousine and Alentejana ones had an intermediate difficulty, and the Mertolenga animals were by far the most heat tolerant.

Effects of weaning and weaning weight on neuroendocrine regulators of feed intake in pigs1,2

A depression in feed intake and growth often occurs in the weaned pig. Spray-dried plasma is often added to nursery diets in an attempt to stimulate feed intake during this lag. The current study evaluated gene expression of appetite regulators in hypothalamus and adipose tissue 4 d after weaning. Barrows (2 wk of age) were cross-fostered to a sow (SOW, n = 8) or weaned and fed a nursery diet containing either 0 or 7% spray-dried plasma (NP, n = 8, and SDP, n = 8, respectively). Piglets were allocated such that 2 size groups existed within each experimental group: small (3.5 to 4.3 kg of BW piglets) and large (4.6 to 5.7 kg of BW piglets) subsets, based on weaning weight (WW), existed within each experimental group: small (3.5 to 4.3 kg piglets) and large (4.6 to 5.7 kg piglets). Animals were killed 4 d after weaning for tissue collection. There was a weaning group x WW interactive effect (P < 0.05) on hypothalamic neuropeptide Y messenger RNA expression, such that expression was least in the small SDP piglets. No WW or weaning group effects were seen on adipose leptin, hypothalamic leptin receptor, or hypothalamic proopiomelanocortin gene expression. An effect of WW was seen on hypothalamic neuropeptide Y, agouti-related protein, orexin, and type 2 orexin receptor gene expression, such that large pigs expressed greater amounts of these transcripts (P < 0.002). Strong positive correlations in gene expression were found among all of these genes, whose products are known to stimulate appetite. Partial correlation controlling for initial WW revealed that preweaning size explained most if not all of these associations. These data suggest that the postweaning expression of appetite-regulating genes is more dependent on preweaning conditions than on weaning diet.

Metabolic Effects of Abomasal l-Carnitine Infusion and Feed Restriction in Lactating Holstein Cows

l-Carnitine is required for mitochondrial fatty acid oxidation, but the effects of carnitine supplementation on nutrient metabolism during dry matter intake depression have not been determined in dairy cows. Studies in other species have revealed responses to l-carnitine that may be of specific benefit to dairy cows during the periparturient period. Eight lactating Holstein cows (132±36 d in milk) were used in a replicated 4×4 Latin square experiment with 14-d periods. Treatments were factorial combinations of abomasal infusion of either water or l-carnitine (20g/d; d 5 to 14) and either ad libitum or restricted intake (50% of previous 5-d dry matter intake; d 10 to 14) of a balanced lactation diet. Liver and muscle biopsies were obtained on d 14 of each period. Feed restriction induced negative balances of energy and metabolizable protein. In feed-restricted cows, carnitine infusion increased 3.5% fat-corrected milk yield compared with those infused with water. Total carnitine concentration in liver was increased in feed-restricted cows infused with carnitine but not in feed-restricted cows infused with water. Carnitine infusion stimulated in vitro oxidation of [1-14C] palmitate to acid-soluble products and decreased the proportion of [1-14C] palmitate that was converted to esterified products by liver slices. Feed-restricted cows infused with carnitine had lower liver total lipid concentration and tended to have decreased triglyceride accumulation compared with feed-restricted cows infused with water. Plasma nonesterified fatty acid concentration was not altered by carnitine infusion but was increased by feed restriction; serum β-hydroxybutyric acid was increased by carnitine infusion in feed-restricted cows. In cows fed for ad libitum intake, carnitine infusion affected β-hydroxybutyric acid, insulin, and urea N in serum, liver glycogen concentration, and in vitro alanine oxidation by liver slices, suggesting that hepatic and peripheral nutrient metabolism was influenced. l-Carnitine infusion effectively decreased liver lipid accumulation during feed restriction as a result of greater capacity for hepatic fatty acid oxidation. Further research examining dietary supplementation of l-carnitine during the periparturient period is warranted.

Dietary Putrescine (1,4-Diaminobutane) Influences Recovery of Turkey Poults Challenged with a Mixed Coccidial Infection

Exogenous dietary putrescine (1,4-diaminobutane) can increase growth rates of neonatal animals, including calves, chicks, and piglets, under nutritional stress. Turkey poults often have a high mortality rate and this may be due to poor initial feeding behavior and inadequate development of the intestinal tract. We conducted an experiment to determine the effect of dietary putrescine supplementation on growth performance and the role of dietary putrescine in prevention and recovery from a coccidial challenge. A total of 160 1-d-old turkey poults were fed a corn and soybean meal–based starter diet supplemented with 0.0 (control), 0.1, 0.2, and 0.3 g/100 g purified putrescine (8 birds/pen, 5 pens/diet). At 14 d of age, half the birds were infected with ∼43,000 sporulated oocysts. The experiment lasted 24 d. Fecal samples were gathered from d 3 to d 5 postinfection by total collection. Ten control and 10 infected birds fed each diet were sampled on d 6 and d 10 postinfection. The induced infection produced significant depressions in growth and feed intake and detrimental morphological changes in the small intestine of poults in the absence of mortality. Weight gains, protein content of jejunum, and morphometric indices of duodenum, jejunum, and ileum were greater in challenged poults fed 0.3 g/100 g putrescine than in controls. We conclude that dietary putrescine supplementation may be beneficial to poult growth, mucosal development of the small intestine, and to recovery from subclinical coccidiosis.

Amino Acid Imbalance-Biochemical Mechanism and Nutritional Aspects

Amino acid imbalances refer to the deleterious effects that occur when a second-limiting amino acid or mixture of amino acid lacking a particular limiting amino acid is supplemented in diets marginal in one or more indispensable amino acids. In spite of variation in the conditions that have been used to induce amino acid imbalances, such as protein level in the diet, the extent of difference in total nitrogen content between basal and imbalanced diets, and kinds of amino acids used as imbalancing agents, the conspicuous common features of amino acid imbalances have been a decreased concentration of the limiting amino acid in blood, depression of feed intake and weight gain, and increased dietary content of the limiting amino acid needed to correct the imbalances. There is strong evidence that a decrease in the concentration of a limiting amino acid detected in the anterior prepyriform cortex of the brain is followed by behavioral effects, especially a decrease in feed intake. This might be due to the competition between the limiting amino acid and the amino acids in the imbalancing mixture for transport from blood into brain. One of the biochemical responses of animals fed amino acid imbalanced diets is a rapid decrease in the concentration of the limiting amino acid, which are due in part to an increase in catabolism of the limiting amino acid by the increased activities of enzymes involved in the catabolism of the amino acid. Practically, specific amino acid imbalances could be induced in swine and poultry diets that have been supplemented with lysine, methionine, tryptophan when threonine, isoleucine, valine, etc. are potentially third- or fourth-limiting in diets. In these cases supplementation of the limiting amino acid could be beneficial in preventing the decrease of feed intake that could otherwise occur as a result of amino acid imbalance.

Effects of Prima gland clover (Trifolium glanduliferum Boiss cv. Prima) consumption on sheep production and meat quality

Gland clover (Trifolium glanduliferum Boiss) is a recently introduced and released clover species for use in Mediterranean agricultural systems in southern Australia. There is little information on the expected animal production from this pasture plant although it is known to contain coumarins. Coumarins may have a direct effect on the production of grazing ruminants through a reduction in feed intake and may also have the ability to influence the flavour and odour of meat. In this study, Merino hogget ewes were grazed on eight 0.5 ha replicate plots sown to monocultures of either Prima gland clover or Dalkeith subterranean clover (Trifolium subterraneum ssp. subterraneum L.). The Prima gland clover was estimated to contain between 80 and 300 mg coumarin/kg dry matter. Three sheep were allocated to the plots on 7 September and 1 sheep from each plot was slaughtered on 29 September. Two additional sheep were allocated to the plots on 28 September and another 2 on 19 October. At the end of the experiment on 8 November, each plot contained 2 sheep that had grazed for 3, 6 or 9 weeks. All sheep were slaughtered at this time. The 2 sheep that remained on the plots from 7 September to 8 November were used for the comparison of animal production between the 2 clover species. Following slaughter, measurements were made of carcass characteristics and meat eating quality. The liveweight gain and wool growth of the 2 treatments were similar over the 9 weeks, however, the sheep on the Prima gland clover plots grew faster over the first 3 weeks. The faster growth rate is consistent with a higher in vitro digestibility of the Prima gland clover at this time. The similarity in feeding value of the 2 clover species indicates that there was no depression in feed intake associated with the Prima gland clover. There were some small significant differences in meat eating quality between the groups. Meat from sheep grazing the Prima gland clover was drier and had a more pleasant taste. These differences are unlikely to be large enough to have any commercial significance. The results indicate that the Prima gland clover has a feeding value at least equivalent to the Dalkeith subterranean clover and that, under the conditions of this experiment, the coumarin concentrations in the Prima gland clover are not high enough to affect either feed intake or the flavour and odour of meat.

Some physiological responses associated with reduced wool growth during blowfly strike in Merino sheep

To examine the effect on wool growth of physiological changes associated with experimental flystrike in superfine Merino wethers. An animal house study comparing experimentally fly struck sheep with non-infected control groups that were pair fed or fed ad libitum. Sheep in the blow fly larval challenge group were each artificially infected with 500 first instar larvae per day for 8 days. Infections were terminated with insecticide on day 10. For all sheep, live weight change, feed intake and body temperature were monitored and blood collected for analysis of haematology, cortisol, serum haptoglobin, serum amyloid A and the pro-inflammatory cytokines, TNFa, IL-1 b, IL-6 and IL-8. Wool growth and staple strength were examined 4 months after infection. Experimental fly strike included moderate fever, depressed feed intake, and elevated cortisol, IL-6, serum amyloid A and haptoglobin. Staple strength was significantly decreased in struck sheep and did not differ between wool from sites adjacent to and remote from strike lesions. The results suggest that depression in feed intake alone is not sufficient to account for the decline in staple strength seen during fly strike. Cortisol, IL-6 and metabolic consequences of the acute phase response are likely to be major contributors to the systemic effects of blowfly strike on wool.

Fos-Positive Neurons Are Increased in the Nucleus of the Solitary Tract and Decreased in the Ventromedial Hypothalamus and Amygdala by a High-Protein Diet in Rats

Transition from a normal- (NP) to a high-protein (HP) diet induces a rapid depression in food intake and a progressive but incomplete return to the initial intake during the succeeding days. The aim of this study was to determine which CNS regions are involved in the HP diet-induced satiety in rats. Brains were collected from 3 groups of adult rats after habituation to an NP diet (21 d), during the transition phase to a HP diet (2 d), or after habituation to the HP diet (21 d). Fos expression was measured in several brain areas that are involved in the control of food intake (solitary tract nucleus, anterior piriform cortex, lateral hypothalamus, arcuate nucleus, posterior para ventricular nucleus, medio ventral hypothalamus, dorso medial hypothalamus, amygdala, and accumbens nucleus). Changes occurred in the majority of these regions during the transition period from the NP diet to the HP diet. After habituation to the HP diet, significant changes in Fos expression were restricted to an increase in the nucleus of the solitary tract and a decrease in the ventromedial hypothalamus and the cortex of the amygdala. Considering the functional characteristics of these areas, the present results suggest that the vagus nerve conveys the information relative to the quantity of protein ingested, that hypothalamic sites regulate food intake and may alter sympathetic nervous system activity, and that higher brain functions such as memory processing by the limbic system or food reward system are involved in the HP diet-induced satiety in rats.

A study on the causes for the elevated n−3 fatty acids in cows' milk of alpine origin

The influence of grass-only diets either from rye-grass-dominated lowland pastures (400 m above sea level) or botanically diverse alpine pastures (2000 m) on the FA profile of milk was investigated using three groups of six Brown Swiss cows each. Two groups were fed grass-only on pasture (P) or freshly harvested in barn (B), both for two experimental periods in the lowlands and, consecutively, two periods on the alp. Group C served as the control, receiving a silage-concentrate diet and permanently staying in the lowlands. Effects of vegetation stage or pasture vs. barn feeding on milk fat composition were negligible. Compared with the control, alpha-linolenic acid (18:3n-3) consumption was elevated in groups P and B (79%; P< 0.001) during the lowland periods but decreased on the alp to the level of C owing to feed intake depression and lower 18:3n-3 concentration in the alpine forage. Average 18:3n-3 contents of milk fat were higher in groups P and B than in C by 33% (P< 0.01) at low and by 96% (P < 0.001) at high altitude, indicating that 18:3n-3 levels in milk were to some extent independent of 18:3n-3 consumption. The cis-9, trans-11 CLA content in milk of grass-fed cows was higher compared with C but lower for the alpine vs. lowland periods whereas the trans-11, cis-13 isomer further increased with altitude. Long-chain n-3 FA and phytanic acid increased while arachidonic acid decreased with grass-only feeding, but none of them responded to altitude. Grass-only feeding increased milk alpha-tocopherol concentration by 86 and 134% at low and high altitude (P < 0.001), respectively. Changes in the ruminal ecosystem due to energy shortage or specific secondary plant metabolites are discussed as possible causes for the high 18:3n-3 concentrations in alpine milk.

Diet-induced obesity impairs mammary development and lactogenesis in murine mammary gland

We have developed a mouse model of diet-induced obesity that shows numerous abnormalities relating to mammary gland function. Animals ate approximately 40% more calories when offered a high-fat diet and gained weight at three times the rate of controls. They exhibited reduced conception rates, increased peripartum pup mortality, and impaired lactogenesis. The impairment of lactogenesis involved lipid accumulation in the secretory epithelial cells indicative of an absence of copius milk secretion. Expression of mRNAs for beta-casein, whey acid protein, and alpha-lactalbumin were all decreased immediately postpartum but recovered as lactation was established over 2-3 days. Expression of acetyl-CoA carboxylase (ACC)-alpha mRNA was also decreased at parturition as was the total enzyme activity, although there was a compensatory increase in the proportion in the active state. By day 10 of lactation, the proportion of ACC in the active state was also decreased in obese animals, indicative of suppression of de novo fatty acid synthesis resulting from the supply of preformed fatty acids in the diet. Although obese animals consumed more calories in the nonpregnant and early pregnant states, they showed a marked depression in fat intake around day 9 of pregnancy before food intake recovered in later pregnancy. Food intake increased dramatically in both lean and obese animals during lactation although total calories consumed were identical in both groups. Thus, despite access to high-energy diets, the obese animals mobilized even more adipose tissue during lactation than their lean counterparts. Obese animals also exhibited marked abnormalities in alveolar development of the mammary gland, which may partially explain the delay in differentiation evident during lactogenesis.

Predictive role of daily coping and affective reactivity in cognitive therapy outcome: Application of a daily process design to psychotherapy research

We hypothesized that patients' initial ability to cope with daily stress would predict their rates of improvement in cognitive therapy (CT). For 1 week at the beginning of CT, 43 adult outpatients with depression and/or anxiety diagnoses completed daily assessments of stressors and associated appraisals, negative cognitions, coping strategies, and negative mood. Depression was assessed at intake and at every treatment session. Even after the statistical control of intake depression level, treatment length, and concurrent medication status, many of the stress and coping variables were associated with rates of depression-reduction in the expected direction. We discuss the findings' implications for CT theory and practice as well as the heuristic value of a daily process design to evaluate the predictive role of patient factors in psychotherapy outcome.

Feed intake and production in sheep fed diets high in sodium and potassium

Salinity is a problem facing many crop and livestock producers in southern Australia. One management option is to revegetate with salt-tolerant plants suitable for animal production. These plants are often halophytic shrubs containing up to 30% ash, predominantly as sodium, potassium, or chloride. This experiment examines the consequences of a high intake of sodium and potassium separately or together on feed intake, digestibility, liveweight change, and wool growth. Twelve groups of 6 weaner wethers were allocated to treatments according to a balanced 3 × 4 factorial design with 3 levels of added potassium (0, 0.38, and 0.77 mol/kg DM equivalent to 0, 15, and 30 g/kg DM) and 4 levels of added sodium (0, 0.87, 2.18, and 3.48 mol/kg DM, equivalent to 0, 20, 50, and 80 g/kg DM) as the chloride salts. The treatment diets were fed to sheep for 6 weeks. Increasing sodium in the diet significantly decreased feed intake, digestibility, liveweight gain, and wool growth either as a main effect or through an interaction with potassium. Organic matter intake was reduced from 1.35 kg at the lowest levels of sodium and potassium to 0.67 kg at the highest levels. Comparing the same 2 groups, liveweight gain was reduced from 144 to 0 g/day, organic matter digestibility from 59.1% to 57.3%, and wool growth from 1.21 to 1.04 mg/cm2.day. The response surfaces indicate that production was depressed even at the lower levels of sodium, whereas high potassium depressed intake, digestibility, and liveweight gain at high levels of sodium only. The interaction between sodium and potassium was always negative at high levels of sodium, indicating that manipulation of the proportions of the 2 elements is unlikely to provide benefits for animal production when total salt levels are high. Although wool growth was depressed at high sodium and potassium, the efficiency of wool growth increased from 10.0 to 15.4 g/kg organic matter intake when the lowest and highest levels of the sodium and potassium were compared. This result may present significant opportunities for the use of saline land to grow fine wool.

Effects of dietary glucogenic precursors and fat on feed intake and carbohydrate status of transition dairy cows.

Twenty-four multiparous Holstein cows were used to determine the effects of dietary fat and glucose precursors on energy status and lactation. The treatment group (T) received 409 g/d (DM basis) of a combination of calcium salts of fatty acids, calcium propionate, and propylene glycol. The control group (C) received 409 g/d of a mixture of calcium salts of fatty acids and ground barley from 14 +/- 0.9 g/d before until 21 d after calving. Dry matter intake was greater (16.1 vs. 13.6 +/- 1.3 kg/d) for T than C during the last week prepartum and did not decrease for T from the previous week, whereas, in C, DM intakes decreased by 3.2 kg/d. Production of milk and milk fat did not differ. There was a tendency for lower protein and increased lactose concentrations in milk from T cows. Milk fat percentage was lower in T at d 7 (5.5 vs. 6.4 +/- 0.5%) and 28 (4.4 vs. 5.5 +/- 0.5%) of lactation. Liver lipid content was numerically lower (7.9 vs. 9.2 +/- 0.9%) and glycogen content was significantly higher (2.4 vs. 2.0 +/- 0.1%) in T vs. C cows on d 7 of lactation. Concentrations of nonesterified fatty acids were lower in blood of T cows on d 2 and 7 of lactation. Over all time points, blood glucose concentrations were higher in T cows pre- (70.75 vs. 62.1 +/- 1.3 mg/dL) and postpartum (60.1 vs. 56.2 +/- 1.1 mg/dL). Insulin concentrations in blood were greater for T (397 vs. 314 +/- 48 pg/mL) both pre- and postpartum. Feeding glucose precursors in combination with rumen inert lipids, compared with feeding barley in combination with the lipids for 2 wk before parturition and 3 wk postpartum helped avoid prepartum feed intake depression and increased blood glucose and insulin and decreased blood NEFA.

Preabsorptive factors are not the main determinants of intake depression induced by a high-protein diet in the rat

The factors involved in the depression of food intake produced by a high-protein diet are still poorly understood. The aim of this study was to assess the role of several preingestive or preabsorptive factors likely to influence food intake when rats were fed ad libitum. Food intake was measured after modifying the composition of the high-protein diet, i.e., the type of proteins, or carbohydrates. Moreover, correlations between high-protein diet intake and the quantity of fluid ingested or stomach volume were studied. By varying the carbohydrate composition (sucrose/cornstarch) and the protein source (soy or gluten or total milk protein) of high-protein diets, we modified the orosensory properties of these diets. However, no differences in food intake were observed between these groups of rats during the transition phase or after adaptation, except during the first day of soy- or gluten-based diets when the depression of food intake was intensified. The depression of high-protein diet intake was neither the consequence of any delay necessary to increase the fluid intake induced by eating a high-protein diet nor due to a marked increase in stomach volume, which might explain enhanced satiety and decreased food intake through the activation of vagal afferent fibers. Our experiments do not indicate a preponderant role for oropharyngeal or preabsorptive factors in the depression of food intake induced by a high-protein diet.

Effect of Salt Level in the Feed on Performance of Red and Fallow Weaner Deer

In Australia, many cropping areas are affected by salt. In these regions, Chenopodiaceous plants, such as Atriplex, Kochia and Bassia spp have been planted to improve soil conditions. These plants have become invaluable feed resources for grazing animals in dry summers, but have a high sodium content. To assess the impact of high salt intake on grazing deer, two experiments were conducted. The first experiment used 30 fallow weaner deer to examine the effect of salt level in the diet on feed intake, water intake and body weight of fallow deer. Salt was added to lucerne chaff at 0, 1.5, 3.0, 4.5 and 6% and fresh water was offered all the time. Increasing the salt level in the diet from 0 to 6% didn't affect feed intake, osmotic pressure and mineral concentration in blood of fallow deer. However, water intake was significantly higher (p0.056) for fallow deer in July and August when salt content was over 3%, suggesting they can ingest over 15 g sodium/day without significant depression in both feed intake and growth rate if the fresh water is available. In the second experiment, 18 red weaner deer were fed lucerne chaff diets containing 1.5, 4.5 and 6.0% salt with 6 deer/diet. The results revealed that feed intake and blood osmotic pressure were similar (p>0.05) for red deer fed different levels of salt although the feed intake declined from 1.91 to 1.67 kg with the increase of salt level from 1.5% to 6.0% in the diet. Water intake was significantly higher for deer fed diets containing over 4.5% salt, but there was no difference in body weight during the experiment. However, no recommendation can be made on the salt tolerance of red deer due to limited increment of salt level in the diet.

Total Subdiaphragmatic Vagotomy Does Not Suppress High Protein Diet–Induced Food Intake Depression in Rats

This study was undertaken to determine whether the subdiaphragmatic vagus nerve is involved in the depression of food intake induced by the ingestion of a high protein diet (P50) in rats. After total subdiaphragmatic vagotomy (Vago group) or sham surgery (Sham group), rats consumed the control diet for a 2-wk recovery period and then both groups consumed the high protein diet for 16 d. Daily food intake, meal pattern analysis and behavioral satiety sequence were measured. Total subdiaphragmatic vagotomy did not modify the daily intake of the control diet or suppress the dramatic depression in food intake produced by acute transition to a high protein diet. However, the daily intake of a high protein diet was slightly reduced under acute conditions or even after adaptation (P < 0.005). Analysis of meal parameters and the behavioral satiety sequence after adaptation indicated no major metabolic distress. In conclusion, these results suggest that the subdiaphragmatic vagus nerve does not constitute an obligatory pathway for the transfer of information to the brain, resulting in a depression of high protein diet intake. In contrast, a defect in this visceral regulating system could reinforce the metabolic-associated food intake depression signal.

The role of melatonin in maintenance of immunological internal environment

Melatonin hormone secretes from the pineal gland during dark period. This study was designed to investigate the effect of daily melatonin administration to chicks on some physiological parameters A total of fifty fawbro chicks of one day old were divided into two groups. The first group was given melatonin orally at a dose of 12ug/100g body weight daily for eight weeks and the other group was used as a control. During this experimental work the following parameters were studied. Daily feed and water intake, body temperature before and after melatonin administration with a general observation of chick's behaviour. Blood samples were collected weekly to study some parameters (total red blood cells, hemoglobin content, packed cell volume and differential leukocytic count). &#x0D; The results showed that, melatonin caused a drop of body temperature with relaxation and sleeping of chicks up to three hours after its administration. This period was accompanied by depression of feed and water intake. Total RBCs count, Hb, PCV, and lymphocytes were significantly increased with a decrease in heterophil / lymphocyte ratio. &#x0D; In conclusion, results of this investigation indicate that melatonin causes calming and sleeping of chicks and improves their feed conversion ratio.These results appear to be the first indication that melatonin does play an important role in immunity and improvement of blood picture. These effects were suggested to be due to the immuno – enhancing and anti-stress actio melatonin.