Changes in body temperature during growth and in response to fasting in growing modern meat type chickens

1. Rectal or core body temperature was determined in a study to examine the effects of fasting in modern meat type broilers at three stages of growth, namely d 19, 33 and 47.

2. There were two treatment groups: fed with feed available ad libitum and fasted. Rectal temperatures were determined at noon (1200?h). At that time, feed was removed from the fasted group. The body temperatures were then determined again after 6, 12, 18 and 24?h.

3. Core body temperatures decreased with fasting. The decrease was evident after as little as 6?h of fasting with a further decline evident by 12?h.

4. Accompanying the decrease in body temperature with fasting there were decreases in the venous concentrations of carbon dioxide in the blood and sodium in the plasma.

5. The decrease in both body temperature and carbon dioxide presumably reflects depressed metabolic rate.

6. Unexpectedly, the core body temperature increased progressively with age in the control fed group (d 19?=?41·04?±?0·02°C, d 33?=?41·65?±?0·05°C, d 47?=?42·21?±?0·12°C).

7. In the fed control group, core body temperatures were reduced at night, when feeding activity would be anticipated to be greatly reduced.     

Lung volume of meat-type chickens

Lung volume (LV) in meat-type chickens was measured by water displacement and was computed as a percentage of body weight (BW). The percentage of LV/BW declined from 2.02 +/- 0.190% at day 1 to 1.38 +/- 0.163% at day 144. Pulmonary hypertension caused by insufficient lung capillary capacity or oxygen exchange area results in right ventricular failure and ascites in meat-type chickens. Insufficient LV in very fast-growing broilers may contribute to this problem. Selection procedures in meat-type chickens should include a method for estimating LV.     

Metabolic responses to fasting and alloxan-induced diabetes mellitus in steers

To induce diabetes mellitus in 8 steers, they were fasted for 96 hours and given 110 mg of alloxan/kg of body weight (IV, in 1 dose) immediately before refeeding. Subsequently, 4 of the steers were treated with insulin (0.1 to 3 U/kg) to control hyperglycemia and 4 were not given insulin. Four control steers were fasted and refed. Fasting increased serum phosphorus, total protein, and bilirubin and decreased serum magnesium and potassium. Refeeding returned serum values of magnesium, potassium, total protein, and bilirubin toward base-line values, regardless of treatment group. However, serum phosphorus remained increased in steers with alloxan-induced diabetes and was not lowered by insulin injections. Sodium and chloride values were depressed in steers with alloxan-induced diabetes; these values remained significantly (P less than 0.05) lower than base-line values, even in steers given insulin. Fat infiltration was evident in the pancreas, liver, and to some extent, kidneys of steers with alloxan-induced diabetes, but was occasionally present in tissues of steers given insulin.     

Metabolic and hormonal responses to neuroleptanalgesia (etorphine and acepromazine) in the horse

Administration of etorphine and acepromazine to horses was associated with an increase in haematocrit, blood glucose, blood lactate and plasma non-esterified fatty acids (NEFA). The rise in plasma NEFA was most striking following injection of the antagonist diprenorphine and could contribute to the production of cardiac arrhythmias. Plasma insulin was depressed at the end of surgery. These changes, plus profuse sweating, are indirect evidence of strong sympathetic stimulation. Plasma cortisol did not alter significantly due to wide individual variation. Venous blood pH fell, reflecting the rise in lactate and venous carbon dioxide tension.     

Immunomodulation by probiotic lactobacilli in layer- and meat-type chickens

1. The aim of the experiments was to evaluate whether selected probiotic lactobacillus strains have different immunomodulating effects in layer- and meat-type strain chickens. 2. Humoral and cellular specific and non-specific immune responses were studied by experiments on cellular proliferation, entry and survival of Salmonella bacteria in gut and spleen leukocytes, immunoglobulin isotypes and specific immunoglobulin titres. 3. The effects of two different feeding regimes (short and continuous feeding) and doses for administration of lactobacilli were studied. 4. The lactobacillus strains that were evaluated showed modulating effects on the immune system of layer- and meat-type chickens. 5. In meat-type strain chickens the lactobacilli had a stimulating effect when the chickens were young (up to 3 weeks) and the dose was relatively high, whereas in layer-type chickens a lower effective dose and discontinuous administration was also effective. 6. Immunoprobiotic lactobacilli can have a positive effect on humoral and cellular immune responses in layer- and meat-type strain chickens, but the lactobacillus strain to be used, the age of the animals and effective dose of lactobacilli to be administered need to be optimised.     

Detection of subgroup J avian leukosis virus infection in Australian meat-type chickens

OBJECTIVE: To determine the extent of avian leukosis virus subgroup J (ALV-J) infection in Australian broiler breeder flocks, using virus isolation and molecular biological detection. Any resultant ALV-J viral isolates to be characterised by neutralisation cross testing in order to determine antigenic relationships to overseas isolates of ALV-J. STUDY DESIGN: Samples of blood, feather pulp, albumen and tumours were obtained from broiler breeder flocks which represented four genetic strains of meat chickens being grown in Victoria, South Australia, NSW and Queensland. Dead and ailing birds were necropsied on farm and samples were collected for microscopic and virological examinations. Virus isolation was carried out in C/O and DF-1 CEF cultures and ALV group specific antigen was detected in culture lysates using AC-ELISA. Micro-neutralisation assay was used for antigenic characterisation of selected isolates. Genomic DNA was isolated from cultured cells, tumours and feather pulp. ALV-J envelope sequences were amplified by PCR using specific ALV-J primers while antibodies against ALV-J were detected by ELISA. RESULTS: A total of 62 ALV-J isolates were recovered and confirmed by PCR from 15 (31.3%) of 48 breeder flocks tested. Antibody to ALV-J was detected in 20 (47.6%) of the 42 flocks tested. Characteristic lesions of myeloid leukosis caused by ALV-J were found in affected flocks. The gross pathological lesions were characterised by skeletal myelocytomas located on the inner sternum and ribs, neoplastic enlargement of the liver, and in some cases gross tumour involvement of the spleen, kidney, trachea, skeletal muscles, bone marrow, skin and gonads. Microscopically, the tumours consisted of immature granulated myelocytes, and were present as focal or diffuse infiltrations in the affected organs. Virus micro-neutralisation assays demonstrated antigenic variation among Australian isolates and to overseas strains of ALV-J. CONCLUSION: ALV-J infection was prevalent in Australian broiler breeder flocks during 2001 to 2003. Australian isolates of ALV-J show a degree of antigenic variation when compared to overseas isolates.     

Sequential feeding of whole wheat to growing broiler chickens

1. Four broiler feeding trials were performed to examine the suitability of a whole wheat sequential feeding regimen for commercial broiler production. The sequential feeding programme gave a continuous cycle of ad libitum access to only whole wheat followed by the same time of access to only a pelleted diet. The pelleted diet provided a concentration of nutrients to balance that provided by the whole wheat. This was called a balancer diet.

2. The first trial used 144 cage‐reared broilers from 28 to 49 d of age. Four different times of access (4, 8, 12 and 24 h) to the two alternate foods were compared. A whole wheat choice‐feeding treatment and a complete single diet treatment were also compared. Whole wheat accounted for over 40% of the broilers’ total food intakes when they were given the sequential feeding treatments of 8 h or greater. The whole wheat intakes of the birds given the 4 h sequential feeding and the choice‐feeding were only 20 and 5% respectively. There was a non linear relationship between the weight gains of the broilers and the length of the sequential feeding period (P< 0.01). The growth rates of the broilers given sequential feeding were lowest (P< 0.05) in the 4‐h feeding periods but highest (P< 0.05) in the 8‐h periods. Weight gains decreased (P< 0.01) linearly as the sequential feeding periods were increased above 8 h.

3. A second trial, using 144 cage‐reared broilers, examined the effect of different balancer compositions or different wheat varieties in 8‐h sequential feeding. The broilers selected more whole wheat in their diet when they were given balancers with increased cereal contents. However, these broilers did not eat enough whole wheat to compensate for the reduced cereal content of the balancers and their overall diets had lower energy: protein ratios. The two different wheat samples did not result in any differences (P> 0.05) in the proportion of whole wheat selected by the broilers.

4. A third trial compared the diet selections, weight gains, food intakes and water excretions of 72 cage‐reared broilers given whole wheat feeding regimens. The growth rates of the broilers given a loose mix of whole wheat and a pelleted balancer diet were similar (P> 0.05) to broilers given a complete single diet. The growth rates of these two groups were 7% greater (P< 0.05) than broilers given choice‐feeding or 8‐h sequential feeding. There were no differences (P> 0.05) in the total amounts of water excreted among the 4 treatments.

5. The fourth trial used 828 broilers distributed in 6 floor pens. They were given either a complete diet or an 8‐h whole wheat sequential feeding regimen from 25 to 46 d of age. The food intakes and the growth rates of the broilers were reduced (P<0–05) in die sequential feeding treatment by 9% and 5% respectively. There was no difference (P> 005) in litter moisture between the 2 treatments.     

Metabolic and microbial responses in western crossbred and Meishan growing pigs fed a high-fiber diet

Four Duroc x White composite crossbred (21.8 +/- 1.0 kg BW) and four 12-wk-old Meishan purebred (20.7 +/- 1.6 kg BW) growing barrows were used to determine the relative breed differences in metabolic and microbial responses to a high-fiber diet. The pigs were trained to consume 700 g of a diet containing 35% (as-fed basis) dehydrated alfalfa meal once daily. The pigs' daily intakes of DM, N, GE, NDF, and ADF were 610 g, 16.6 g, 2.64 Mcal, 150 g, and 88 g, respectively. On d 12 after surgical catheterization of the portal vein, ileal vein, and carotid artery, a 3-d total urine and feces collection was conducted. On d 24 after surgery, each pig was placed in an open-circuit calorimeter, and its catheters were connected to a system for simultaneous measurements of oxygen consumption by portal-drained viscera and by whole body, and the net portal absorption of VFA after a 24-h fasting and during a 5-h postprandial period. The VFA measured included acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids. A second 3-d total urine and feces collection was conducted on d 30 after surgery. There were no differences (P = 0.13) between the first and second collections in apparent total-tract digestibility coefficients for nutrients and N retention of pigs. Compared with Duroc x White composite crossbred pigs, Meishan pigs had lower (P = 0.05) apparent digestibility coefficients for DM, N, NDF, hemicellulose, and N retention, but their portal-drained viscera used a greater (P = 0.05) fraction of whole-body oxygen consumption. No differences (P = 0.12) were found between Duroc x White composite crossbred and Meishan pigs in total viable bacteria and cellulolytic bacteria from fecal samples, in vitro digestibility of alfalfa NDF fractions by fecal inocula, whole-body oxygen consumption, net portal absorption of VFA, total energy of absorbed VFA, and the potential of absorbed VFA for meeting the energy needs for whole-body heat production. These results indicate that, in contrast to previous beliefs, the ability of Meishan growing pigs to utilize a high-fiber diet is not superior to that of Duroc x White composite crossbred growing pigs.     

Metabolic adaptations to heat stress in growing cattle

To differentiate between the effects of heat stress (HS) and decreased dry matter intake (DMI) on physiological and metabolic variables in growing beef cattle, we conducted an experiment in which a thermoneutral (TN) control group (n = 6) was pair fed (PF) to match nutrient intake with heat-stressed Holstein bull calves (n = 6). Bulls (4 to 5 mo old, 135 kg body weight [BW]) housed in climate-controlled chambers were subjected to 2 experimental periods (P): (1) TN (18 °C to 20 °C) and ad libitum intake for 9 d, and (2) HS (cyclical daily temperatures ranging from 29.4 °C to 40.0 °C) and ad libitum intake or PF (in TN conditions) for 9 d. During each period, blood was collected daily and all calves were subjected to an intravenous insulin tolerance test (ITT) on day 7 and a glucose tolerance test (GTT) on day 8. Heat stress reduced (12%) DMI and by design, PF calves had similar nutrient intake reductions. During P1, BW gain was similar between environments and averaged 1.25 kg/d, and both HS and PF reduced (P < 0.01) average daily gain (-0.09 kg/d) during P2. Compared to PF, HS decreased (P < 0.05) basal circulating glucose concentrations (7%) and tended (P < 0.07) to increase (30%) plasma insulin concentrations, but neither HS nor PF altered plasma nonesterified fatty acid concentrations. Although there were no treatment differences in P2, both HS and PF increased (P < 0.05) plasma urea nitrogen concentrations (75%) compared with P1. In contrast to P1, both HS and PF had increased (16%) glucose disposal, but compared with PF, HS calves had a greater (67%; P < 0.05) insulin response to the GTT. Neither period nor environment acutely affected insulin action, but during P2, calves in both environments tended (P = 0.11) to have a blunted overall glucose response to the ITT. Independent of reduced nutrient intake, HS alters post-absorptive carbohydrate (basal and stimulated) metabolism, characterized primarily by increased basal insulin concentrations and insulin response to a GTT. However, HS-induced reduction in feed intake appears to fully explain decreased average daily gain in Holstein bull calves.     

Ocular responses to ammonia in broiler chickens

In two trials, 60 male commercial broilers were placed in each of eight environmentally controlled chambers receiving 0, 25, 50, or 75 ppm aerial ammonia from 1 to 28 days. Birds exposed to 25 ppm (lower concentration) ammonia gas developed ocular abnormalities but at a slower rate when compared with birds exposed to 50 and 75 ppm (higher concentrations). Birds exposed to higher concentrations also developed more severe lesions. With little atmospheric ammonia present after 28 days of the grow-out stage, the corneas indicated signs of healing. Lymphocytes and heterophils were seen in the iris at 49 days in ammonia-exposed birds even when ammonia exposure was terminated at 28 days. The lower ammonia concentrations resulted in abnormalities that were slight when compared with those seen at the higher ammonia concentrations. As measured by the incidence of inflammatory infiltrates in the trachea, lung, and air sacs, respiratory tract tissues did not appear to be affected by any tested level of aerial ammonia. The findings in this investigation represent the first report indicating that ammonia-induced uveitis in chickens clears rapidly after exposure to ammonia ceases.     

Depletion of glycogen reserves in fasting broiler chickens

1. Male broiler chickens were killed at various times up to 36 h after withdrawal of food; hepatic and muscle glycogen concentrations and pH were compared with those of control birds given continuous access to food and water. 2. Liver glycogen was reduced to negligible concentrations (less than 1 mg/g) within 6 h of food deprivation and the initial pH was elevated. 3. Withdrawal of food had no effect on glycogen concentrations in the m. pectoralis superficialis (PS) but reduced them in the m. biceps femoris (BF); the reduction was significant after 12 h. Ultimate pH was elevated by fasting in the BF, but not the PS.     

Responses of growing chickens to high dietary contents of rapeseed meal

1. The feeding of diets high in rapeseed meal to broiler chicks caused enlargement of the liver and may have caused some mortality.

2. High‐glucosinolate Brassica napus rapeseed meal caused a higher incidence of haemorrhagic livers among broiler chicks than did B. campestris meal and a low‐glucosinoate B. napus meal was without effect.

3. White Leghorn cockerels were of little use in studying the aetiology of haemorrhagic liver after feeding rapeseed meal if mortality was used as a criterion. They may be of value in studies of liver function.     

瘤胃保护性蛋氨酸和细菌脂多糖对肉牛的营养代谢和激素水平的影响

<正>1材料和方法1.1试验设计选取初始体重为262±6.3kg的杂交安格斯肉牛20头,牛棚地面铺2.54cm的橡胶,可以用自来水自动冲洗。所有的肉牛在上午7:00和晚上19:00饲喂1.4%单位体重(以DM为基础)的粗日粮(表1),自由饮水,整个试验时间持续19d,在饲喂粗饲料的14d内所有的肉牛基本适应了该种日粮,其余的5d为收集样品期。其中没有添加     

Effects of rumen-protected methionine supplementation and bacterial lipopolysaccharide infusion on nitrogen metabolism and hormonal responses of growing beef steers

Metabolic demand for sulfur-containing AA increases during inflammation in nonruminants. Therefore, Met supplementation may alleviate the negative effects of infection on N balance. Effects of gram-negative bacterial lipopolysaccharide (LPS) and supplemental dietary Met on N balance, serum hormones and haptoglobin, and plasma urea-N and AA were evaluated in 20 Angus-cross steers (BW = 262 +/- 6.3 kg). Treatments (2 x 2 factorial) were infusion of no LPS (-LPS) or a prolonged low dose of LPS (+LPS) and dietary supplementation of no (-MET) or 14 g/d (+MET) of rumen-protected Met (providing 7.9 g/d of dl-Met). Steers were adapted to a roughage-based diet (DMI = 1.4% of BW daily) and supplemental Met for 14 d, and were then infused (1 mL/min via intravenous catheter) with LPS on d 1 (2 microg/kg of BW) and 3 (1 microg/kg of BW) of a 5-d collection period. Blood was collected on d 1, before LPS infusion, and at 2, 4, 6, 8, 10, 12, and 24 h after LPS challenge. Diet samples, feed refusals, feces, and urine were collected daily for 5 d. Rectal temperature and serum concentrations of cortisol, prolactin, tumor necrosis factor-alpha, and haptoglobin increased, whereas thyroxine and triiodothyronine decreased for +LPS vs. -LPS steers (LPS x h; P < 0.01). Plasma urea-N was greater for +LPS than -LPS steers (LPS; P = 0.03), and serum IGF-1 was not affected (P > or = 0.26) by LPS or Met. Plasma concentrations of Thr, Lys, Leu, Ile, Phe, Trp, Asn, Glu, and Orn decreased, plasma Ala increased, and Gly and Ser initially increased, then declined in +LPS vs. -LPS steers (LPS x h; P < or = 0.04). Plasma Met was greater for +MET than -MET steers before LPS infusion, but declined in +MET steers after LPS infusion (LPS x Met x h; P < 0.01). By design, DMI was not different, but DM digested was less (P = 0.04) for +LPS than -LPS steers. Infusion of LPS did not affect (P > or = 0.24) N intake, fecal N excretion, or N digested, but resulted in greater (P < 0.01) urinary N excretion and less (P < 0.01) N retention. The absence of an LPS x Met interaction (P = 0.26) for N retention indicates that supplemental Met does not improve the N utilization of growing beef steers exposed to a gram-negative bacterial endotoxin. Decreases in plasma concentrations of several essential AA in +LPS steers suggest that metabolic demand for these AA likely increased in steers exposed to endotoxin.     

Amino acid requirements of growing chickens.

1. Using 18% protein diets (N times 6-25), consisting mainly of conventional ingredients of known amino acid composition, the amino acid requirements as percentages of diet and of dietary protein respectively for broiler chickens between 14 and 28 d of age were found to be: threonine 0-50-0-52% of diet (2-8-2-9% of dietary protein); glycine 0-48-0-50 (2-7-2-8); valine 0-69-0-71 (3-8-3-9); methionine+cystine 0-58 (3-2); isoleucine smaller than 0-48 (smaller than 2-7); leucine smaller than 1-05 (smaller than 5-8); tyrosine+phenylalanine 1-09-1-12 (6-1-6-2); lysine 0-87 (4-8); histidine smaller than 0-34 (smaller than 1-9); arginine smaller than 0-76 (smaller than 4-2); tryptophan smaller than 0-14 (smaller than 0-78). 2. Values found were in general lower than those determined using diets consisting entirely of purified amino acids and the reasons for this are discussed.