Hypocholesterolaemia in dogs with dominance aggression

Serum lipids and lipoprotein concentrations have been associated with dominance aggression in humans. The aim of this study was to investigate the link between serum lipids, including cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC) to HDL-C ratio and dominance aggression in dogs. Levels of serum TC, triglyceride and HDL-C were significantly lower in dogs with dominance aggression compared with non-aggressive dogs (P < 0.001). These results suggest that a relationship exists between serum lipid profile and dominance aggression in dogs, and hypocholesterolaemia exists in dogs with dominance aggression.     

Effects of tryptophan supplementation on aggression among group-housed gestating sows

The objective of this study was to determine the effects of dietary Trp supplementation on mixing-induced aggression and the associated stress, and on reproductive performance in gestating sows. After weaning, sows were mixed in pens with electronic sow feeders on concrete-slatted floors. Each pen housed 21 ± 2.8 sows, with approximately 2.7 ± 0.43 m(2)/sow of floor space allowance. Multiparous sows (n = 168) from 8 breeding groups were used, with 4 groups assigned to a control diet and 4 groups assigned to a high-Trp diet. Control sows received corn- and soybean meal-based diets throughout gestation (0.15% Trp) and lactation (0.21% Trp). Three days before and after mixing, sows assigned to the high-Trp treatment received approximately 2.3 times the dietary Trp (0.35% in the gestation diet and 0.48% in the lactation diet) fed to control sows. Six focal sows (2 sows from each of parity 1, 2, and 3 or greater) in each pen were designated and videotaped for 72 h after mixing to determine the type and number of aggressive interactions among sows. Before and 48 h after mixing, saliva samples were collected from focal sows, and scratches were assessed on all sows. Data were analyzed using the FREQ and GLIMMIX procedures (SAS Inst. Inc., Cary, NC). Aggression among sows was intense during the initial 6 h and decreased between 6 and 72 h after mixing. The initial aggression caused scratches and increased cortisol concentrations (P < 0.05). Mature sows tended to fight for longer periods (112 vs. 52 s/h per sow, SE = 23.8; P < 0.10) but had fewer scratches caused by aggression (injury score = 4.3 vs. 6.5, SE = 1.13; P < 0.01) than parity-1 sows. Supplementation of dietary Trp reduced the total duration of head-to-head knocking (P < 0.05) but did not affect other aggressive behaviors. There was no difference between dietary treatments in injury scores or saliva cortisol concentrations. Sows in the high-Trp treatment had more total piglets born (12.5 vs. 10.5 pigs/litter, SE = 0.55; P < 0.05) and more stillborn piglets (1.5 vs. 0.8 pigs/litter, SE = 0.20; P < 0.05), but had no significant change (P = 0.12) in piglets born alive (10.8 vs. 9.7 pigs/litter, SE = 0.42) compared with control sows. The results indicate that the initial aggression after mixing caused more injuries in young sows than in mature sows. Supplementation of dietary Trp at 2.3 times the control amount for a short period did not effectively reduce aggression and the associated stress in sows at mixing.     

Effect of dietary chloride content on the elimination of bromide by dogs

The effect of dietary chloride content (0·2, 0·4 and 1·3 per cent chloride on a dry matter basis) on the disposition of a single oral dose of bromide (14 mg kg⁻¹ was evaluated in normal beagles. Increasing the dietary chloride content from 0·2 to 1·3 per cent resulted in a significant decrease in the mean apparent elimination half-life from 69 ± 22 days to 24 ± 7 days. The mean area under the concentration curve ( ) for dogs fed 1·3 per cent chloride was significantly smaller than the for dogs fed 0·2 per cent chloride. Dietary chloride had no effect on the maximum serum concentrations (C_max) or on the time (T_max) to reach the maximum concentrations. The steady-state serum bromide concentrations predicted from the single dose data for daily doses of 14 mg kg⁻¹ of bromide were significantly lower in dogs fed 1·3 per cent chloride (310 ± 150 mg litre⁻¹) than in dogs fed 0·2 per cent chloride (1950 ± 1140 mg litre⁻¹). The predicted mean daily doses of bromide necessary to maintain serum levels within the therapeutic range for dogs fed 1·3 per cent chloride (43 ± 13 mg kg⁻¹) were almost twice as high as the dose estimated for dogs fed 0·4 per cent chloride (22 ± 3 mg kg⁻¹) and nearly three times as high as the dose estimated for dogs fed 0·2 per cent chloride (15 ± 4 mg kg^−l). These differences were statistically significant (P=0·002).     

Effect of dietary iron content on hematologic and other measures of iron adequacy in dogs

Eighteen 9- to 10-week old Beagles were fed casein-based diets (4,710 kcal of metabolizable energy/kg of body weight) containing either 12, 80, or 160 mg of iron/kg of diet. Growth and feed consumption were monitored throughout the 47-day study. Hematocrit (Hct), hemoglobin (Hb) concentration, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), RBC numbers, erythrocyte protoporphyrin (EP) concentration, serum iron concentration, serum total iron-binding capacity (TIBC), and serum ferritin concentration were determined weekly. Growth rate and feed efficiency were not significantly influenced by dietary iron content. At 14 days, Hb concentration, Hct, MCV, MCH, RBC numbers, and serum iron concentration were significantly (P less than 0.05) lower in dogs fed the 12 mg/kg diet, and remained significantly low for the remainder of the study. Erythrocyte protoporphyrin concentration increased significantly (P less than 0.05) by 14 days in dogs fed the basal diet, and remained significantly high relative to that in dogs of the other dietary groups for the remainder of the study. Serum ferritin concentration decreased in dogs of the group fed the basal diet, with a significant (P less than 0.05) difference beyond day 42. Differences in Hct, MCH, MCV, or hemoglobin, serum iron, serum ferritin, or EP concentration were not found between groups fed 80 and 160 mg of iron/kg of diet. Liver nonheme iron content was significantly (P less than 0.05) affected by dietary iron content.     

色氨酸对蛋白质代谢的影响及调控机制

色氨酸作为畜禽的功能性氨基酸,除了作为底物合成蛋白质外,还具有调控蛋白质代谢的功能。本文就色氨酸对蛋白质代谢的影响及调控机制作一综述。     

圈舍卫生状况及日粮色氨酸对断奶仔猪生产性能的影响

卫生状况的改变会影响动物色氨酸的代谢．可能会导致色氨酸供应不足。本试验旨在研究轻度炎症与色氨酸对动物生长性能、色氨酸代谢、血浆氨基酸浓度、血浆球蛋白、谷胱甘肽浓度等方面的影响。试验显示脏乱圈舍环境不仅可造成断奶仔猪轻度炎症反应．还会引起仔猪对色氨酸代谢的改变,表明充足的色氨酸有益于断奶仔猪生长．     

Influence of dietary protein content and source on colonic fermentative activity in dogs differing in body size and digestive tolerance

Low-consistency, high-moisture feces have been observed in large dogs (Canis lupus familiaris), compared with small dogs, and particularly in sensitive breeds (e.g., German Shepherd dogs). The aim of this work was to determine if greater colonic protein fermentation is responsible for poorer fecal quality in large sensitive dogs. Twenty-seven bitches were allotted to 4 groups based on size and digestive sensitivity: small, medium, large tolerant, and large sensitive. Five experimental diets varying in protein source [highly digestible wheat gluten (WG) vs. medium digestible poultry meal (PM), and protein concentration from 21.4 to 21.6 (LP) to 38.2 to 39.2% CP (HP)] were tested. Diets were fed for 14 d and followed by a 12-d transition period. Digestive fermentation by-products were investigated in fresh stools [ammonia, phenol, indole, and short chain fatty acids including acetate, propionate, and butyrate (C2 to C4 SCFA), branched-chain fatty acids (BCFA), and valerate] and in urine (phenol and indole). Bacterial populations in feces were identified. The PM diets resulted in greater fecal concentrations of ammonia, BCFA, valerate, indole, and C2 to C4 SCFA than WG diets (P = 0.002, P < 0.001, P = 0.039, P = 0.003, and P = 0.012, respectively). Greater concentrations of ammonia, BCFA, and valerate were found in the feces of dogs fed HP compared with LP diets (P < 0.001, P < 0.001, and P = 0.012, respectively). The concentrations of ammonia, valerate, phenol, and indole in feces of large sensitive dogs were greater (P < 0.001, P < 0.001, P = 0.002, and P = 0.019, respectively) compared with the other groups. The Enterococcus populations were greater in feces of dogs fed with PMHP rather than WGLP diets (P = 0.006). Urinary phenol and indole excretion was greater when dogs were fed PM than WG diets (P < 0.001 and P = 0.038, respectively) and HP than LP diets (P = 0.001 and P = 0.087, respectively). Large sensitive dogs were prone to excrete a greater quantity of phenol in urine (P < 0.001). A diet formulated with highly digestible protein, such as WG, led to reduced concentrations of protein-based fermentation products in feces together with improved fecal quality in dogs, especially in large sensitive ones. Poor fecal quality in large sensitive dogs could be partly related to the pattern of protein fermentation in the hindgut.     

Effects of protein concentration on responses to dietary tryptophan by chicks

1. Chicks were fed from 4 to 18 d on 40 diets containing all combinations of 8 crude protein (CP) concentrations (from 160 to 300 g/kg) and 5 tryptophan concentrations (from 7.5 to 13.5 g tryptophan/kg CP). 2. At each protein concentration there were responses in growth rate and in efficiency of food utilisation to supplementation with tryptophan. Curves were fitted to estimate the maximum response at each protein concentration. 3. The amounts of tryptophan required (g/kg) for maximum growth and maximum food efficiency were each linear functions of dietary protein concentration. The chick's requirement for tryptophan can be expressed as 12 g/kg CP. 4. It is concluded that a fixed ratio of tryptophan to protein should be specified in practical diet formulation, rather than a minimum dietary concentration of tryptophan.     

Effect of dietary protein on functional, morphologic, and histologic changes of the kidney during compensatory renal growth in dogs

Two diets similar in caloric density and mineral content, but markedly different in protein content, were used to study the effects of dietary protein on renal function and morphologic and histopathologic changes in dogs that had functional renal tissue reduced by seven-eights nephrectomy. The effects of moderate protein intake (MPrI = 15% protein; dry-matter basis) and high-protein intake (HPrI = 31% protein; dry-matter basis) were studied for the initial 7 months (period 1 [P1]) after renal mass reduction. Diets were then switched between groups during the following 7 months (period 2 [P2]) to evaluate the effects of increased or decreased protein intake. The HPrI caused significantly (P less than 0.05) greater glomerular filtration rate (GFR) and renal growth than did MPrI during P1. Dogs that maintained HPrI during P1 and MPrI during P2 (group 1) had significant (P less than 0.05) reduction in GFR during P2. Dogs that maintained MPrI during P1 and HPrI during P2 (group 2) had significant (P less than 0.05) improvement in GFR and renal growth during P2. At the end of the study, renal reserve was evaluated in both groups of dogs before and after group 1 was returned to HPrI for 2 weeks. During this 2-week feeding trial, group-1 dogs had marked improvement in renal reserve, relative to group 2, and GFR increased to the terminal P1 values. Results indicate a possible residual benefit from HPrI during the early phase of compensatory renal growth in the form of functional compensatory memory to HPrI. The severity of renal lesions was indistinguishable between dogs of dietary groups during both study phases.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hypercalcaemia in two dogs caused by excessive dietary supplementation of vitamin D

A three-year-old Border collie was presented with a two-week history of lethargy, stiff gait, polydipsia and polyuria. Biochemical analysis revealed hypercalcaemia. Serum concentrations of 25-hydroxyvitamin D (25[OH]D) and 1,25-dihydroxyvitamin D (1,25[OH]2D) were markedly elevated and parathyroid hormone was undetectable. Subsequent analysis of the dog's diet revealed that the food contained excessive amounts of vitamin D. The hypercalcaemia resolved following treatment with bisphosphonates and dietary change. Hypervitaminosis D was diagnosed in a second unrelated dog, which had been fed the same brand of dog food as case 1. The dog was also hypercalcaemic and had markedly elevated serum concentrations of 25(OH)D and 1,25(OH)2D. Hypervitaminosis D in dogs has been reported to occur secondarily to ingestion of either rodenticides containing cholecalciferol or antipsoriatic ointments that contain vitamin D analogues. Hypervitaminosis D has also been reported following the treatment of hypoparathyroidism. To the authors' knowledge, this is the first report of hypervitaminosis D in dogs following the accidental over supplementation of a commercial diet with vitamin D. While the benefits of adequate dietary vitamin D are well established in dogs, the potential deleterious effects of over supplementation of vitamin D should also be acknowledged.     

Influence of dietary protein level, amino acid supplementation, and dietary energy levels on growing-finishing pig performance and carcass composition

Two experiments were conducted to determine the effects of feeding reduced-CP, AA-supplemented diets at two ambient temperatures (Exp. 1) or three levels of dietary NE (Exp. 2) on pig performance and carcass composition. In Exp. 1, 240 mixed-sex pigs were used to test whether projected differences in heat increment associated with diet composition affect pig performance. There were 10 replications of each treatment with four pigs per pen. For the 28-d trial, average initial and final BW were 28.7 kg and 47.5 kg, respectively. Pigs were maintained in a thermoneutral (23 degrees C) or heat-stressed (33 degrees C) environment and fed a 16% CP diet, a 12% CP diet, or a 12% CP diet supplemented with crystalline Lys, Trp, and Thr (on an as-fed basis). Pigs gained at similar rates when fed the 16% CP diet or the 12% CP diet supplemented with Lys, Trp, and Thr (P > 0.10). Pigs fed the 12% CP, AA-supplemented diet had a gain:feed similar to pigs fed the 16% CP diet when housed in the 23 degrees C environment but had a lower gain:feed in the 33 degrees C environment (diet x temperature, P < 0.01). In Exp. 2, 702 gilts were allotted to six treatments with nine replicates per treatment. Average initial and final BW were 25.3 and 109.7 kg, respectively. Gilts were fed two levels of CP (high CP with minimal crystalline AA supplementation or low CP with supplementation of Lys, Trp, Thr, and Met) and three levels of NE (high, medium, or low) in a 2 x 3 factorial arrangement. A four-phase feeding program was used, with diets containing apparent digestible Lys levels of 0.96, 0.75, 0.60, and 0.48% switched at a pig BW of 41.0, 58.8, and 82.3 kg, respectively. Pigs fed the low-CP, AA-supplemented diets had rates of growth and feed intake similar to pigs fed the high-CP diets. Dietary NE interacted with CP level for gain:feed (P < 0.06). A decrease in dietary NE from the highest NE level decreased gain:feed in pigs fed the high-CP diet; however, gain:feed declined in pigs fed the low-CP, AA-supplemented diet only when dietary NE was decreased to the lowest level. There was a slight reduction in longissimus area in pigs fed the low-CP diets (P < 0.08), but other estimates of carcass muscle did not differ (P > 0.10). These data suggest that pigs fed low-CP, AA-supplemented diets have performance and carcass characteristics similar to pigs fed higher levels of CP and that alterations in dietary NE do not have a discernible effect on pig performance or carcass composition.     

Effect of dietary fish oil and vitamin E supplementation on hematologic and serum biochemical analytes and oxidative status in young dogs

Fifteen healthy dogs received a basal diet supplemented with either 12.4 g of sunflower oil, 0.6 g of sunflower oil and 7 g of menhaden fish oil, or 0.6 g of sunflower oil and 7 g of menhaden fish oil plus 0.18 g of alpha-tocopherol acetate for twelve weeks. There was no significant diet effect on platelet aggregation, lipid peroxidation, or standard hematologic and biochemical parameters, with the exception of decreased triglycerides in dogs supplemented with fish oil. These data demonstrate that this level of fish oil supplementation in dogs does not require vitamin E supplementation above recommended dosage and may prove beneficial in the treatment of hyperlipidemia in the dog.     

Effects of tryptophan supplementation on cashmere fiber characteristics, serum tryptophan, and related hormone concentrations in cashmere goats

This study was designed to investigate the effects of tryptophan (Trp) supplementation on cashmere fiber characteristics and on serum Trp, melatonin (MEL), prolactin (PRL), insulin-like growth factor 1 (IGF-1), triiodothyronine (T(3)), and thyroxine (T(4)) concentrations in cashmere goats during the cashmere fast-growth period. Thirty-six Liaoning cashmere wether goats were stratified on the basis of body weight (28 ± 0.8 kg) and assigned randomly to 1 of the following 4 rumen-protected Trp treatments: 0, 2.0, 4.0, and 6.0 g per goat per day. The experimental period lasted 137 d. Blood samples were collected monthly during the daytime (8:00 AM) and at night (8:00 PM). Tryptophan supplementation improved cashmere growth rates, cashmere weight, and body weight (P = 0.001) and increased serum Trp levels, nighttime MEL concentrations, IGF-1, and T(3) and T(4) concentrations (P < 0.05). Across the treatments and sampling months, a highly positive correlation between cashmere growth rate and nighttime serum MEL concentrations was observed (r = 0.879, P = 0.001). A moderately negative correlation between cashmere growth rates and serum PRL concentrations during the day and at night (r(day) = -0.645, P = 0.007; r(night) = -0.583, P = 0.018) was observed. A moderately positive correlation between the cashmere growth rate and the daytime serum IGF-1 concentration (r = 0.536, P = 0.032) was observed, and no correlation was found between the cashmere growth rate and the other serum hormone concentrations. These data indicate that changes in serum concentrations of MEL, IGF-1, and PRL are related to cashmere growth in Liaoning cashmere goats during the cashmere fast-growth period. Under the experimental conditions of the current trial, we suggest that Trp may promote cashmere growth by increasing daytime IGF-1 and nighttime MEL secretion.     

Effect of dietary corn oil supplementation on equine gastric fluid acid, sodium, and prostaglandin E2 content before and during pentagastrin infusion

The effect of corn oil (approximately 60% [wt/vol] linoleic acid) dietary supplementation on various components of equine gastric secretion was studied by use of a repeated-measures experimental design. Four healthy adult ponies were surgically fitted with gastric cannulas. The ponies were then fed a free-choice hay diet for 5 weeks, which was followed by 5 weeks of the same diet supplemented with 45 mL of corn oil daily. Gastric contents were analyzed under basal and pentagastrin-stimulated conditions once weekly during the latter 2 weeks on each diet. Gastric contents were collected at 30-minute intervals, and volume, hydrogen ion concentration, sodium content, and prostaglandin E2 (PGE2) content were measured. Data were analyzed by a linear fixed-effect modeling procedure. During the diet supplemented with corn oil, the ponies had, under basal and pentagastrin-stimulated conditions, significantly decreased acid output and significantly increased PGE2 and sodium outputs compared to those measured before corn oil supplementation. We conclude that corn oil supplementation may be an effective and inexpensive way to increase the protective properties of equine glandular gastric mucosa. This could be particularly helpful in reducing the chances of ulceration associated with nonsteroidal anti-inflammatory drug (NSAID) administration.