Homeostatic responses to water deprivation or hemorrhage in lactating and non-lactating Bedouin goats

Three lactating and three non-lactating black Bedouin goats were subjected to four days of water deprivation or to hemorrhage. Four days of water deprivation caused body wt losses of 32 and 23% and plasma volume losses of 30 and 34% in lactating and non-lactating goats respectively. Plasma osmolality increased 17 and 15% in lactating and non-lactating goats. Plasma arginine vasopressin concentration rose from about 5 pg/ml to a mean of 36 pg/ml. Plasma renin activity increased from about 0.7 ng/ml/hr to a mean of 3.45 ng/ml/hr in lactating and to 3.15 ng/ml/hr in non-lactating goats. At 4.5 hr post-rehydration plasma osmolality and plasma vasopressin concentration were back to normal in non-lactating, but still elevated in lactating goats. Plasma renin activity increased after rehydration. Rapid blood volume loss of 21-28% increased plasma vasopressin concentration to 16-35 pg/ml in non-lactating and to 70 or greater than 500 pg/ml in lactating goats. It is concluded that black Bedouin goats are well adapted to endure severe dehydration and rapid rehydration, but that they (especially lactating animals) react strongly to rapid volume depletion.     

Effect of water restriction on lactation performance of Aardi goats under heat stress conditions

This study was conducted to evaluate the effect of water restriction on lactation performance in Aardi goats. The experiment divided into 3 periods each of 6 days; control, water restriction and rehydration. Nine lactating Aardi goats in early lactation were divided into two groups. One group (n = 5) received 50% and the other group (n = 4) received 25% restriction of drinking water relative to their consumed water during control period. Both groups exhibited a fall in dry matter intake with almost a similar rate. Live weight loss during water restriction was similar in both groups (8 and 6% in 50 and 25% water restriction, respectively). Milk production was also reduced by 20 and 18% with 50 and 25% water restriction, respectively. Milk fat percentage was lower in goats that received 25% restriction while it was maintained unchanged in the 50% restriction group. Total solids of milk tended to decrease in goats with 25% water restriction without any change in milk osmolality. Whereas, milk osmolality increased without any alterations in total solids of milk with 50% water restriction. It could be concluded that lactating Aardi goats possess a high capacity of withstanding water restriction when it was coupled with higher environmental temperature.     

Reproductive period affects water intake in heat-stressed dehydrated goats

Water intake following dehydration was studied in pregnant (N = 5), lactating (N = 4) and nonpregnant, nonlactating (N = 5) Swedish domestic goats (Capra hircus) to investigate if reproductive period affected drinking. Plasma cortisol concentration and the hematocrit value were measured to evaluate stress. The goats were water deprived from 9.00 h until 15.05 h the next day. They were fed at 7.00 and 15.20 h. On the second day, ambient temperature was increased from 20°C to 38–39.5°C for 5.15 h to accelerate water losses. Water temperature during erhydration was 35 ± 1°C. Plasma Na concentration and osmolality increased most in dehydrated and heat-stressed pregnant and lactating goats. Pregnant goats lost 2.2 kg of their body weight. They drank 3.5 l immediately, followed by 2.5 l during afternoon eating. Lactating goats lost 4.9 kg and drank 6.3 l at once, and 3.9 l during feeding. Nonpregnant, nonlactating goats lost 1.7 kg and drank 2.6 l followed by 0.6 l. The large water consumption in pregnant and lactating goats caused hyponatremia and hemodilution, but they continued to drink during the night (0.5 ± 0.2 l and 0.8 ± 0.5 l, respectively). Renal free water clearance increased in all periods, with a long-lasting water diuresis during pregnancy. Plasma cortisol concentrations and the hematocrit values rose in connection with water intake. These results imply that the thirst center became less sensitive to inhibitory signals from the oropharyngeal tract and the diluted blood plasma during pregnancy and lactation. Catching sight of water was the most exciting procedure during these experiments.     

Effects of dehydration,rehydration, and hyperhydration in the lactating and non-lactating black Moroccan goat

The effects of water deprivation, rehydration and hyperhydration were investigated in the black Moroccan goat (Capra hircus). Mean daily water intake was 46 ± 5 ml/kg in lactating and 36 ± 4 ml/kg in non-lactating black Moroccan goats, and milk production 21 ± 1 ml/kg. Mean urine excretion was 8 ± 2 ml/kg body weight in both groups, and the daily water losses via evaporation and feces were estimated at 23 ± 3 ml/kg during lactation and 28 ± 4 ml/kg during non-lactation. Forty-eight hours of water deprivation caused a body weight loss of 9% and 6% in lactating and non-lactating goats, respectively, and a drop of 28% in milk production with only a slight decrease in food intake. After rehydration, the elevated plasma osmolality as well as Na and total protein concentrations returned to basal values within 2–3 hr, indicating a rapid absorption of the ingested water, but urine excretion did not increase. After hyperhydration (10% of body weight), 46% of the load was excreted by the kidneys within 6 hr. In conclusion, black Moroccan goats have a low water turnover, and they can retain water upon rehydration but not store excess water after hyperhydration.     

Water intake induced by water deprivation in the quail,Coturnix coturnix japonica

Mechanisms inducing drinking after water deprivation, and mechanisms terminating drinking after rehydration, were investigated in the quail, Coturnix coturnix japonica. 1. Water intake was induced after 4 h of water deprivation, and the amount of water drunk increased in proportion to the period of water deprivation. Drinking occurred immediately after deprivation. Drinking occurred immediately after deprived birds were given access to water, and continued for periods proportional to the period of water deprivation. 2. Plasma angiotensin II concentration increased, as did plasma osmolality and Na+ concentration, and blood volume decreased after water deprivation. The increase in plasma angiotensin II concentration and decrease in blood volume occurred soon after the start of water deprivation, whereas plasma osmolality and Na+ concentration did not increase until at least 4 h after the start of water deprivation. 3. These results indicate that extracellular dehydration and angiotensin II are responsible for the significant drinking that follows 4 h of water deprivation, and that cellular dehydration is also involved in the stimulation of drinking that occurs after longer periods of water deprivation. 4. Plasma osmolality and Na+ concentration in birds deprived of water for 48 h quickly returned to normal levels after the birds were allowed access to water. Plasma angiotensin II levels and blood volume also approached the values measured prior to water deprivation. However, the rate and degree of restoration of normal values were reduced, and normal values were not restored even after 1.5 h or rehydration when drinking terminated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of intermittent watering on water balance and feed intake in male Ethiopian Somali goats

The objective of this study was to investigate the regulation of water balance and dry matter (DM) intake of male Ethiopian Somali goats. Twenty-eight goats were grouped into four treatments; goats watered every day (W1), every 2nd day (W2), every 3rd day (W3) and every 4th day (W4) for a total period of 72 days. Plasma sodium and potassium were analyzed by flame photometry, plasma osmolality by freezing point depression, plasma protein concentration by TS refractometry, and the plasma vasopressin concentration by radioimmunoassay. Goats were fed grass hay ad libitum and were given 200 g of concentrates daily. The calculated daily water intake (ml/kg BW^0.75) of W1, W2, W3 and W4 was 128 ± 4, 86 ± 4, 88 ± 4 and 78 ± 4, respectively, (P < 0.001, W1 versus the other groups). Calculated total concentrates intake did not change, whereas Group W2 and W4 consumed less hay on days of water deprivation (W1 versus W2, P < 0.01; W1 versus W4, P < 0.001). Plasma sodium concentration of W1 was 143 ± 1 mmol/l. Intermittent watering increased plasma sodium concentration from 140 or 141 ± 1 mmol/l to 145 or 146 ± 1 mmol/l every 2nd day in group W2. In W3, it increased from 139 ± 1 to 146 ± 1 mmol/l and in W4 from 137 ± 1 to 149 ± 1 mmol/l (P < 0.001 for all) on days after watering compared to last day of water deprivation, respectively. Corresponding changes were observed in plasma osmolality. Total plasma protein concentration increased only in W3 from 65 ± 1 to 67 ± 1 mmol/l on day 3 (P < 0.01) and in W4 from 65 ± 1 to 67 and 68 ± 1 mmol/l on days 3 and 4, respectively (P < 0.05). The plasma vasopressin concentration of W1 was close to 0.80 ± 0.28 pmol/l on all days, but it increased on dehydration days in W2 (P < 0.05). In W3, the vasopressin concentration increased from 0.95 or 1.19 pmol/l the day after watering to 3.11 ± 0.28 pmol/l on day 3 (P < 0.01). In W4, it was 0.82 ± 0.31 pmol/l the day after watering and reached 6.06 ± 0.31 pmol/l on day 4 (P < 0.001). We conclude that male Ethiopian Somali goats can be watered once every 3rd days, and that longer interval is not recommended because it demands marked mobilization of water saving mechanisms and causes decreased DM intake.     

Water deprivation in lactating rats: Changes in nucleolar dry mass of paraventricular and supraoptic neurones

Summary The separation of function between and within the paraventricular (PV) and supraoptic (SO) nuclei was investigated in the rat. Nucleolar dry mass of PV and SO neurones was measured to detect increased synthetic activity after water deprivation for 3 days, lactation for 8 days or water deprivation during days 5 to 8 of lactation. Lactation or water deprivation increased nucleolar dry mass in both PV and SO neurones. These stimuli caused similar nucleolar changes in PV neurones, but water deprivation caused greater changes in SO neurones than lactation. The effects of lactation and water deprivation were additive for both SO and PV neurones. Furosemide was used to intensify the dehydration stimulus to determine whether such intensification could have caused the greater nucleolar changes when lactation and water deprivation were combined. For PV neurones this was not the case, but remained a possibility for SO neurones. Measurements of serum osmolality in the experimental groups were ranked as follows: water deprivation + furosemide > lactation + water deprivation > water deprivation > lactation = virgin control. Loss of body weight was similar in the first two groups but less during water deprivation alone. Although milk yield fell, milk was obtained by the litters of lactating animals throughout the period of water deprivation.     

Effect of farm and simulated laboratory cold environmental conditions on the performance and physiological responses of lactating dairy cows supplemented with bovine somatotropin (BST)

A study was conducted to evaluate the effect of bovine somatotropin (BST) supplementation in twelve lactating dairy cows maintained in cold environmental conditions. Six cows were injected daily with 25 mg of BST; the other six were injected with a control vehicle. Cows were maintained under standard dairy management during mid-winter for 30 days. Milk production was recorded twice daily, and blood samples were taken weekly. Animals were then transferred to environmentally controlled chambers and exposed to cycling thermoneutral (15° to 20° C) and cycling cold (–5° to +5° C) temperatures for 10 days in a split-reversal design. Milk production, feed and water intake, body weights and rectal temperatures were monitored. Blood samples were taken on days 1, 3, 5, 8 and 10 of each period and analyzed for plasma triiodothyronine (T³), thyroxine (T⁴), cortisol, insulin and prolactin. Under farm conditions, BST-treated cows produced 11% more milk than control-treated cows and in environmentally controlled chambers produced 17.4% more milk. No differences due to BST in feed or water intake, body weights or rectal temperatures were found under laboratory conditions. Plasma T³ and insulin increased due to BST treatment while no effect was found on cortisol, prolactin or T⁴. The results showed that the benefits of BST supplementation in lactating dairy cows were achieved under cold environmental conditions.     

Influence of weather conditions on milk production and rectal temperature of Holsteins fed two levels of concentrate

Twelve lactating Holstein cows in 2nd lactation were allocated randomly, six each, to two feeding treatments: high concentrate (1 kg dairy concentrate to 2 kg milk produced) and low concentrate (1 kg dairy concentrate to 4 kg milk produced) from 7 to 106 days postcalving. Forage and water were provided adalibitum. Milk and butter fat yields and rectal temperatures were examined in relation to 9 weather variables (minimum, maximum and mean temperatures, relative humidity, temperature-humidity index (THI), radiation, wind velocity and mean temperature of the previous day). Averages for milk yield, fat yield and rectal temperature were respectively 20.4 kg, 0.7 kg and 38.9°C for the high concentrate treatment and 18.4 kg, 0.6 kg and 38.6°C for the low concentrate treatment. Weather conditions accounted for 5.6%, 0.8% and 10.8% of the day to day variation in milk yield, fat yield and rectal remperature, respectively, for the high concentrate group and 29.4%, 9.7% and 0.6%, respectively, for the low concentrate group. Only measures of ambient temperature, especially mean temperature, were closely associated with these traits.     

The effect of cultivated mixed-species green fodder on intake,milk production and milk composition of housed dairy goats

The majority of New Zealand dairy goat farmers utilise cultivated green-fed fodder dominated by perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.), but evidence from other ruminant species suggests that milk production may be improved when using a more diverse array of species within the green fodder. The aim of this experiment was to determine whether feeding lactating dairy goats a mixed-species green fodder (MF, consisting of perennial ryegrass, timothy (Phleum pratense L.), prairie grass (Bromus willdenowii Kunth), white clover, red clover (Trifolium pratense L.), lucerne (Medicago sativa L.), chicory (Cichorium intybus L.) and plantain (Plantago lanceolata L.) improves dietary intake, milk yield and composition compared with a standard ryegrass and white clover green fodder (SF). Thirty-six mid-lactation goats were housed indoors in pairs and split into two groups (A and B). The trial was split into three periods – firstly a uniformity period of 6 days, in which all goats were fed a combination of both green fodder types, followed by two treatment periods (P1 and P2) of 12 days, respectively. For P1, group A was fed MF and group B was fed SF, and then the group diets were switched for P2. Goats fed MF had 13% greater dry matter intake and 7% greater milk yield than goats fed SF. In addition, the milk protein and fat concentration of goats fed MF were 4% greater than for those fed SF, whereas there was no effect on milk lactose concentration. There was no treatment effect on the levels of protein, glucose, urea or non-esterified fatty acids in the blood of the goats. An effect of green fodder type on milk fat profile was demonstrated, with proportions of pentadecylic acid (C15:0), cis-vaccenic acid (C18:1 c11), linoleic acid (C18:2 n6) and α-linolenic acid (C18:3 n3) being increased in response to MF consumption. In contrast, iso-C15 and iso-C17 proportions were lesser. In summary, this study demonstrated that goats fed MF increased green fodder intake and milk production compared with goats fed SF. The green fodder type affected the fatty acid profile of goat’s milk, with MF increasing the levels of beneficial polyunsaturated omega fatty acids (linoleic and α-linolenic acids).     

The excretion of prostacyclin (PGI2) in milk and its possible role as a vasodilator in the mammary gland of goats

1. Prostacyclin production in mammary gland of two lactating goats measured as the excretion in milk of 6-ketoprostaglandin F1 alpha (6-KPGF1 alpha) was followed for 16 days before, during and after exogenous administration of recombinant bovine growth hormone (GH). 2. 6-KPGF1 alpha was detected in all milk samples in concentrations ranging from 32-99 pg/ml milk independently of the time of sampling. 3. GH-treatment significantly increased milk yield, the concentration and excretion of 6-KPGF1 alpha in milk. 4. The concentration of milk 6-KPGF1 alpha was positively correlated with milk yield in the high (R2 = 0.35), but not in the low yielding goat (R2 = 0.003). 5. The possible role of prostacyclin as a local vasodilator in the mammary gland of goats is discussed.     

Effects of water deprivation on urea metabolism in camels, desert sheep and desert goats fed dry desert grass

1. The effects of water restriction and complete water deprivation on nitrogen retention and urea recycling were examined in camels, desert sheep and desert goats fed only dry desert grass of 3.2% crude protein content. 2. All three species were in negative nitrogen balance when water was available ad libitum. 3. In camels urea recycling was consistently high (94-97%) and nitrogen balance did not change with treatment. 4. In sheep and goats urea recycling increased from 75% to 94% (sheep) and from 79% to 95% (goats) during water deprivation, and nitrogen balance improved to positive values. 5. In all species water deprivation depressed dry matter intake and increased apparent digestibility of dry matter and nitrogen. 6. The effects of water restriction were generally intermediate. 7. These results suggest that nitrogen metabolism in adult domestic livestock raised by nomadic pastoralists in Sudan is not harmed, and may in fact be improved by short periods of water deprivation.     

Influence of pregnancy, lactation and environment on some clinical chemical reference values in Danish landrace dairy goats (Capra hircus) of different parity--I. Electrolytes and enzymes.

1. Plasma calcium, magnesium, inorganic phosphorus, sodium and potassium concentrations, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and creatine kinase activities were determined in young and adult non-pregnant non-lactating, early and late non-lactating pregnant and early, mid- and late non-pregnant lactating Danish landrace goats in five herds. The purpose was to determine the influence of pregnancy and lactation on the levels of these parameters and the effect of age and parity on the changes. 2. Calcium, phosphorus, alanine aminotransferase, alkaline phosphatase and aspartate aminotransferase decreased in late gestation. Magnesium and creatine kinase decreased in early lactating goats but increased in subsequent lactation periods. Sodium and potassium fluctuated little during pregnancy and lactation. Calcium, magnesium and potassium profiles were inversely, while phosphorus was directly, proportional to parity. 3. There were significant differences in most ions and enzymes between goats of different herds (within the same physiological state). 4. The transferases and creatine kinase were higher in young goats than in old ones, while alkaline phosphatase was unpredictably high or low in individual goats. 5. Alterations in the level of plasma electrolytes and enzyme activities occur due to pregnancy and lactation and the degree depends on age and parity, influenced also by environment.     

Plasma levels of arginine vasotocin,prolactin, aldosterone and corticosterone during prolonged dehydration in the domestic flowl: effect of dietary NaCl

Three groups of White Plymouth Rock laying hens were adapted to three levels of dietary NaCl: low-NaCl food with tap water (LOW), high-NaCl food (1% NaCl w/w added) with tap water (HT), and high-NaCl food with 0.5% NaCl for drinking (HS). The birds were subjected to water deprivation (dehydration) for 18 days. Blood sampling was done at 2-4 day intervals. Plasma concentrations of arginine vasotocin (AVT), prolactin (PRL), aldosterone (ALDO) and corticosterone (CS) were determined by radioimmunoassay. Plasma osmolality, sodium, chloride, and potassium were also determined. In the normally hydrated hens fully adapted to the diets, there was a stepwise increase from LOW to HS in plasma osmolality (305, 315, 332 mOsm, for LOW, HT and HS, respectively), [Na+] (144, 153, 161 mM) and [Cl-] (109, 119, 127 mM) as well as in [AVT] (6, 14, 18 pg/ml) and [PRL] (16, 24, 34 ng/ml). Regressing [AVT] on osmolality gave a slope of 0.30 pg . ml-1/mOsm and a threshold of 273 mOsm. The slope of [PRL] on osmolality was 0.73 ng . ml-1/mOsm. The correlation coefficient of [AVT] and [PRL] was 0.67. LOW had high [ALDO] (165 pg/ml) which was suppressed to low levels in HT and HS (5-8 pg/ml), while [CS] was the same in all groups (0.9-1.1 ng/ml). Plasma [K+] was decreased in the high-NaCl groups (5.8 mM in LOW, 4.4 and 4.7 mM in HT and HS). Dehydration resulted within 2 days generally in a sharp (5-15%) increase in osmolality, [Na+] and [Cl-], which thereafter increased more slowly during the remaining 16 days in all groups, with the slowest increase in LOW. The levels of osmolality [Na+] and [Cl-] were 5% lower in LOW than in HT and HS, which showed the same levels during the dehydration period. Plasma [AVT] and [PRL] increased 2-4 fold within 2 days of dehydration; [AVT] reached a plateau at 29 pg/ml in all groups, but [PRL] continued to rise in all groups, fastest in LOW, reaching similar levels in all groups after 14-18 days of dehydration, about 85 ng/ml. The correlation coefficient of [AVT] and [PRL] was decreased by half (to 0.32) during dehydration. Plasma [ALDO] increased in all groups with dehydration, 1.7 fold in LOW and 3-6 fold in HT and HS, but the levels reached in HT and HS were only 15-30% of that seen in LOW.(ABSTRACT TRUNCATED AT 400 WORDS)     

Water movements after an intraruminal water load in pregnant and lactating Sardi sheep

The effects of an intraruminal load of 3 litres of water on body water movements was compared in Sardi sheep during the last month of pregnancy, lactation and a non-pregnant, non-lactating control period. Before the water load, rumen fluid volume, estimated by polyethylene glycol was similar in pregnant, compared to control, animals and 27% higher in lactating sheep. After the water load, rumen volume returned to pre-hydration level in 1 h during pregnancy, after 3 h during lactation and in the control period. Rumen osmolality decreased by 40% and remained at this low level for 3 h after the water load in all physiological periods. When the water load was tritiated water (TOH), the rate of TOH transfer into plasma was faster during the last month of pregnancy than during the control period. Plasma osmolality and proteins decreased in response to the water load. No differences in these responses were observed between pregnancy, lactation and the control period. Water diuresis began in the first 30 min following the water load in pregnant ewes and in the second 30 min in lactating and control ewes. The diuresis was also more pronounced in pregnant, than in non-pregnant, states. These results indicate that water is more rapidly absorbed from the gastrointestinal tract in pregnant, rather than in non-pregnant, sheep. This may partly explain the increased water turnover seen during pregnancy.     

Feeding a High Concentrate Diet Down-Regulates Expression of ACACA,LPL and SCD and Modifies Milk Composition in Lactating Goats

High concentrate diets are fed to early and mid-lactation stages dairy ruminants to meet the energy demands for high milk production in modern milk industry. The present study evaluated the effects of a high concentrate diet on milk fat and milk composition, especially, cis-9, trans-11 CLA content in milk and gene expression of lactating goats. Eight mid-lactating goats with rumen fistula were randomly assigned into a high concentrate diet (HCD) group and low concentrate diet (LCD) group. High concentrate diet feeding significantly increased lipopolysaccharides (LPS) in plasma and decreased milk fat content, vaccenic acid (VA) and cis-9, trans-11 CLA in milk of the lactating goats. The mRNA expression levels of sterol regulatory element binding protein B 1c (SREBP1c), lipoprotein lipase (LPL), fatty acid synthetase (FASN) and acetyl-CoA carboxylase α (ACACA, ACCα) involving in lipid metabolism were analyzed, and ACACA and LPL all decreased in their expression level in the mammary glands of goats fed a high concentrate diet. DNA methylation rate of stearoyl-CoA desaturase (SCD) was elevated and decreased, and SCD mRNA and protein expression was reduced significantly in the mammary glands of goats fed a high concentrate diet. In conclusion, feeding a high concentrate diet to lactating goats decreases milk fat and reduced expression of SCD in the mammary gland, which finally induced cis-9, trans-11 CLA content in milk.     

Selective Brain Cooling Reduces Water Turnover in Dehydrated Sheep

In artiodactyls, arterial blood destined for the brain can be cooled through counter-current heat exchange within the cavernous sinus via a process called selective brain cooling. We test the hypothesis that selective brain cooling, which results in lowered hypothalamic temperature, contributes to water conservation in sheep. Nine Dorper sheep, instrumented to provide measurements of carotid blood and brain temperature, were dosed with deuterium oxide (D₂O), exposed to heat for 8 days (40◦C for 6-h per day) and deprived of water for the last five days (days 3 to 8). Plasma osmolality increased and the body water fraction decreased over the five days of water deprivation, with the sheep losing 16.7% of their body mass. Following water deprivation, both the mean 24h carotid blood temperature and the mean 24h brain temperature increased, but carotid blood temperature increased more than did brain temperature resulting in increased selective brain cooling. There was considerable inter-individual variation in the degree to which individual sheep used selective brain cooling. In general, sheep spent more time using selective brain cooling, and it was of greater magnitude, when dehydrated compared to when they were euhydrated. We found a significant positive correlation between selective brain cooling magnitude and osmolality (an index of hydration state). Both the magnitude of selective brain cooling and the proportion of time that sheep spent selective brain cooling were negatively correlated with water turnover. Sheep that used selective brain cooling more frequently, and with greater magnitude, lost less water than did conspecifics using selective brain cooling less efficiently. Our results show that a 50kg sheep can save 2.6L of water per day (~60% of daily water intake) when it employs selective brain cooling for 50% of the day during heat exposure. We conclude that selective brain cooling has a water conservation function in artiodactyls.     

Effects of water deprivation and rehydration on c-Fos and FosB staining in the rat supraoptic nucleus and lamina terminalis region

We studied cFos and FosB staining in the supraoptic nucleus (SON) the organum vasculosum of the lamina terminalis (OVLT) and the median preoptic nucleus (MnPO) in adult male rats after water deprivation (24 h, n = 11; 48 h, n = 12) and water deprivation with rehydration (22 h + water, n = 11; 46 h + water, n = 10). Control rats (n = 15) had water available ad libitum. Separate sets of serial sections from each brain were processed for immunocytochemistry using primary antibodies against either c-Fos or FosB protein. Plasma osmolality, vasopressin, hematocrit, and plasma proteins were measured in separate groups (n = 6-7). The number of c-Fos-positive cells in the SON was significantly increased after 24 and 48 h of water deprivation. In contrast, rehydrated groups were not different from control. Water deprivation significantly increased c-Fos staining in both the OVLT and the MnPO, but c-Fos staining was not altered by rehydration. FosB staining in the SON was significantly increased only by 48-h water deprivation, and this effect was significantly decreased by rehydration. In the MnPO and OVLT, FosB staining was significantly increased by water deprivation, and, like c-Fos staining, these increases were not affected by rehydration. Water deprivation significantly increased osmolality and hematocrit, as well as plasma protein and vasopressin concentrations. Plasma measurements from rehydrated rats were not different from control. We conclude that water deprivation and rehydration differentially affect c-Fos and FosB staining in a region-dependent manner.     

Assessing unintended effects of a mammary-specific transgene at the whole animal level in host and non-target animals

Risk assessment in transgenic plants is intrinsically different than that for transgenic animals; however both require the verification of proper transgene function and in conjunction, an estimate of any unintended effects caused by expression of the transgene. This work was designed to gather data regarding methodologies to detect pleiotropic effects at the whole animal level using a line of transgenic goats that produce the antimicrobial protein human lysozyme (hLZ) in their milk with the goal of using the milk to treat childhood diarrhea. Metabolomics was used to determine the serum metabolite profile of both the host (lactating does) and non-target organism (kid goats raised on control or hLZ milk) prior to weaning (60 days), at weaning (90 days) and 1 month post-weaning (120 days). In addition, intestinal histology of the kid goats was also carried out. Histological analysis of intestinal segments of the pre-weaning group revealed significantly wider duodenal villi (p = 0.014) and significantly longer villi (p = 0.028) and deeper crypts (p = 0.030) in the ileum of kid goats consuming hLZ milk. Serum metabolomics was capable of detecting differences over time but revealed no significant differences in metabolites between control and hLZ fed kids after correction for false discovery rate. Serum metabolomics of control or hLZ lactating does showed only one significant difference in an unknown metabolite (q = 0.0422). The results as a whole indicate that consumption of hLZ milk results in positive or insignificant intestinal morphology and metabolic changes. This work contributes to the establishment of the safety and durability of the hLZ mammary-specific transgene.     

Water balance during saline imbibition in the Mongolian gerbil (Meriones unguiculatus)

1. There were few changes in the water balance of gerbils drinking 0.25 and 0.50 M NaCl solutions for 5 days. 2. Imbibition of 0.75 and 1.0 M saline resulted in some dehydration of the body fluids and considerable depletion of the neural lobe vasopressin store. 3. Although large amounts of NaCl were excreted, the maximum urine osmolality was considerably less than that found following water deprivation. 4. The imbibition of 1.0 M saline caused similar changes in water balance to water deprivation showing that little, if any, water was gained from this solution.