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PubMed1989

Digestive tract clearance of broilers cooped or deprived of water.

Feed is withdrawn from broilers to facilitate digestive tract clearance before processing. This research examined the effects of cooping and water deprivation on contents of the digestive tract during feed withdrawal in two experiments. Broilers were reared to 48 days of age on litter in a windowless house. Corn-soybean meal diets and water were provided ad libitum. In the first experiment, broilers were continuously fed before feed withdrawal. In the second experiment, broilers were placed on a meal-feeding regimen of 1.5 h on feed and 4.5 h off feed for 42 h prior to feed withdrawal. Withdrawal began at the end of a 1.5-h feeding period. At the time of feed withdrawal, broilers were cooped, left on litter without water, or left on litter with water available. At 2, 4, 6, and 8 h after withdrawal, ten broilers from each treatment were killed and the crop, proventriculus plus gizzard, and small intestine were removed. The weight of the contents of each segment was determined. Water deprivation did not change the weight of contents in any segment. Cooped broilers retained digesta in the crop and proventriculus plus gizzard for a longer time than broilers on litter. The combination of meal feeding and cooping soon after feed withdrawal greatly increased the quantity of digesta in the crop 8 h after feed withdrawal. Cooping should be delayed until the crop is empty. Meal feeding increases the time required to accomplish this.

Animals↗

PubMed1991

Effects of sodium bicarbonate and potassium chloride drinking water supplementation. 2. Meat and carcass characteristics of broilers grown under thermoneutral and cyclic heat-stress conditions.

Two broiler trials were conducted to investigate the effect on post-mortem carcass and meat quality of NaHCO3 and KCl drinking water supplementation under thermoneutral and cyclic heat-stress climatic conditions. Water chill carcass weight change, water- and oven-cooked breast filled yields, and breast meat tenderness were measured. In Trial 1, neither environmental regimen, nor water treatments, nor their interaction was a significant (P less than .05) source of variation for the parameters measured. In Trial 2, environmental regimen was a highly significant (P less than .01) source of variability for chilled carcass weight change; the cyclic heat-stressed broiler carcasses gained more weight than the thermoneutral (control) broiler carcasses during ice-water chilling. Oven-cooked fillet yield was significantly (P less than .05) affected by environmental regimen; fillets from cyclic heat-stressed broilers had lower yields than thermoneutral (control) broiler fillets. Drinking water treatments were a significant (P less than .05) source of variation for breast meat tenderness in Trial 2. Broilers given .5% NaHCO3 from 5 to 8 wk of age had higher shear resistance values than broilers given a combination of .5% NaHCO3 and .5% KCl or tap water-fed controls. Breast meat shear values were negatively correlated (P less than .05) with 8-wk broiler body weight and 5- to 8-wk gain.

Analysis of Variance↗

PubMedDate not supplied

Evaluation of Salmonella serotype distributions from commercial broiler hatcheries and grower houses.

By conventional trayliner (hatcheries) and drag swab assembly (broiler houses) culture methods, the isolation distribution of Salmonella serotypes from five commercial broiler hatcheries (three sample times) and 13 broiler farms (eight sample times) was evaluated. A total of 11 different Salmonella serotypes were isolated from hatcheries, with Salmonella heidelberg (9/30) and Salmonella kentucky (6/30) accounting for 50% of the total isolations. Of 700 chick paperpad trayliners sampled, regardless of lot (breeder flock source) or hatchery, 12% were positive for Salmonella. When 10 individual trayliners were cultured from individual lots (same breeder flock source), Salmonella was detected in 24/57 lots (42%). Multiple serotypes were simultaneously isolated from the same lot on three occasions (6%). Of the 21 lots that were serially sampled, the Salmonella serotype detected was different within lots eight times (38%) on at least one occasion of two or more sampling times. Of the 196 individual broiler houses sampled, 44 were positive for Salmonella (42%). Twelve different serotypes were isolated from broiler houses during this study. The serotypes isolated most frequently were S. heidelberg (34/94) and S. kentucky (22/94). These two serotypes accounted for 59.6% (56/94) of the total broiler house isolations. Of the 38 houses that were serially sampled, two or more serotypes were detected in the same broiler house on 20 occasions (53%). Of the 38 serially sampled houses (four or more times), a consistent Salmonella serotype was detected in five houses (13%). In only 5 of the 38 (13%) serially sampled houses did we fail to detect Salmonella on four or more samplings. No significant difference in Salmonella isolation frequency was observed between poultry houses using new or used litter. These data support previous findings indicating that paratyphoid Salmonella serotypes are prevalent in some broiler hatcheries and houses. Further, the observation of multiple serotypes simultaneously and serially isolated from the same breeder hatchery lots suggests that breeder flocks may be infected with more than one serotype, possibly providing a source for multiple serotype infections in progeny grower flocks.

Animal Husbandry↗

PubMedDate not supplied

Survival of Salmonella in the crop contents of market-age broilers during feed withdrawal.

Recent studies have indicated that crop contamination increases during preslaughter feed withdrawal and that contaminated crop contents may serve as an important source of Salmonella entry into poultry processing plants. During the present study, we evaluated the effect of preslaughter feed withdrawal on crop pH and Salmonella crop contamination in broilers from three commercial broiler flocks. The effect of experimental feed withdrawal on crop pH, lactic acid concentration, and Salmonella crop contamination was also evaluated in market-age broilers challenged experimentally with Salmonella typhimurium. Crop pH increased significantly (P < 0.05) from 3.64 +/- 0.25 before feed removal to 5.14 +/- 0.72 after 8 hr of feed withdrawal in broilers from commercial flocks. The incidence of Salmonella crop contamination in the commercial broilers increased (P < 0.05) from 3.3% before feed removal to 12.6% after 8 hr of feed withdrawal. Similarly, crop pH increased (P < 0.05) by a magnitude of approximately 1 unit in broilers after 8 hr of experimental feed withdrawal. The population of S. typhimurium in the crops of the experimentally challenged broilers increased (P < 0.05) by approximately 1 log unit during the 8-hr experimental feed withdrawal. The concentration of lactic acid in the crop of the broilers during experimental feed withdrawal decreased (P < 0.01) from a range of 119-135 mumol/ml before feed removal to a range of 22-32 mumol/ml after 8 hr of feed withdrawal. The results indicated that feed withdrawal resulted in a decrease in lactic acid in the crop, accompanied by an increase in crop pH, and an increase in Salmonella crop contamination.

Animals↗

PubMedDate not supplied

Packed cell volume reference intervals to aid in the diagnosis of anemia and polycythemia in young broiler chickens.

Packed cell volume (PCV) reference intervals were established for use in diagnosing anemia and polycythemia in young broiler chickens. Blood samples were collected from one hundred twenty 3-to-49-day-old clinically healthy conventionally reared broiler chickens. PCVs were determined and analyzed. PCVs regressed significantly (P less than 0.025) on age, which shows that neonatal physiologic anemia occurs in broiler chickens, as well as in mammals and specific-pathogen-free (SPF) chickens. The definition for anemia in broiler chicks varies with age. We defined anemia as a PCV less than or equal to 26%, 29%, 33%, 32%, 33%, 33%, 31%, and 28% for broiler chickens, 3, 7, 14, 21, 28, 35, 42, and 49 days old, respectively. We define polycythemia as a PCV greater than or equal to 42%, 43%, 41%, 40%, 42%, 42%, 41%, and 40% for broiler chickens 3, 7, 14, 21, 28, 35, 42, and 49 days old, respectively. Otherwise, broiler chickens have PCVs within established reference intervals. Results provide guidelines for detecting anemia and polycythemia in young broiler chickens of various ages.

Analysis of Variance↗

PubMedDate not supplied

Rapid serological profiling by enzyme-linked immunosorbent assay. IV. Association of infectious bursal disease serology with broiler flock performance.

Breeder and broiler flocks were serologically evaluated using a multiple enzyme-linked immunosorbent assay (M-ELISA). The serologic status of two commercial broiler-breeder flocks and their progeny was monitored, and 840 sera were promptly assessed for antibodies against six infectious agents using the M-ELISA. Breeder flocks were sampled at lay, and broiler chicks were hatched from fertile eggs collected on the scheduled lay date of the breeders. The broiler chicks were placed for growout as eight separate flocks (four from each breeder), and the serologic survey of broilers included sequentially sampling each flock five times between 1 day of age and market. Association of broiler vaccination schedules, mortality, and condemnation data with the temporal serologic data obtained indicated that the earlier appearance of active antibody against infectious bursal disease (IBD) in some unvaccinated flocks was associated with subsequent higher growout mortality and with the poorer overall performance that these flocks experienced. The results of this serologic survey also demonstrated that if a constant, well-timed monitoring program had not been used, major serologic differences between flocks would not have been detected. Serologic profiles of selected broiler flocks by virus-neutralization (VN) tests for infectious bronchitis virus (IBV) and reovirus or by hemagglutination-inhibition (HI) tests for Newcastle disease virus (NDV) compared favorably with the serologic profiles obtained by M-ELISA. Comparison of vaccination histories with serologic results derived from M-ELISA, VN or HI tests indicated that response to vaccination for IBV and NDV at 1 day was either blocked or significantly delayed by moderate levels of maternal antibody and/or were suppressed by an apparent field outbreak of IBD that occurred in all eight broiler flocks.

Animals↗

PubMedDate not supplied

Histomorphometry and vitamin D metabolism of valgus-varus deformity in broiler chickens.

Vitamin D metabolite levels and tibiotarsal histomorphometric characteristics were determined in 49-day-old male broilers. Valgus-varus bone deformity was present in 5.2% and tibial dyschondroplasia (TD) in 3% of these broilers, which were raised on floor litter under seemingly normal nutritional, space, and lighting conditions. No significant weight differences were observed between normal and lame broilers. The plasma levels of 25-OH-D were the same in lame and normal broilers. However, 1,25-(OH)2D plasma levels were reduced 28% in broilers with valgus-varus deformities but normal in broilers with TD. Anatomically, there were three different patterns of bone development in the undecalcified mid-diaphyseal sections. The pattern with the least periosteal growth, lowest tetracycline labeling, and smallest marrow cavity was most often seen in valgus-varus deformities. Patterns with greatest periosteal growth, high tetracycline labeling, and larger marrow cavities were more representative of normal broilers. It was hypothesized that defective prostaglandin metabolism reduced 1,25-(OH)2D levels, contributing to the overall reduction in bone formation and bone resorption observed in broilers with valgus-varus bone deformity.

Animals↗

PubMedDate not supplied

Nutrient absorption and changes in blood plasma of stunted broilers.

Broilers were collected from three farms in which there was high mortality, stunting, and leg weakness characteristic of a condition referred to by various names, including infectious stunting, pale bird syndrome, malabsorption syndrome, and helicopter disease. Broilers were also collected from a fourth farm in which no birds showed the syndrome. Most but not all of the stunted broilers exhibited paleness, poor feather development, and broken feather shafts. Most lesions and abnormalities of the internal organs were of low frequency and not correlated with stunting. Bleaching of the pancreas, however, was found in 47% of the stunted broilers. Compared with normal-sized broilers from the same farms, the stunted broilers had increased plasma protein, decreased plasma pigment, and a sometimes increased liver glycogen level. The increase in protein was the result of increased levels of alpha, beta 1, gamma 1 and gamma 2 globulins. The levels of plasma glucose, body temperature, breast muscle moisture, packed cell volume, and intestinal pH were not affected in stunted broilers. Likewise, no difference could be demonstrated between stunted and normal broilers in the in vitro intestinal absorption of glucose or L-methionine.

Animals↗

PubMed2026

A Review on Heat Stress in Broiler Chickens: Mechanisms, Effects and Mitigation Strategies.

BACKGROUND: Heat stress (HS) is a major environmental challenge for broilers, particularly under rising global temperatures and high humidity. Broiler chickens are highly susceptible because of their rapid growth rate, high metabolic heat production, limited thermoregulatory capacity and genetic selection for fast growth. OBJECTIVE: This review aims to synthesise current evidence, evaluate the effectiveness of existing mitigation strategies, identify key knowledge gaps and provide future research directions to improve broiler resilience, welfare and productivity under increasingly HS conditions. METHODS: This review synthesised evidence published between 2010 and 2025 on the physiological, metabolic, intestinal, immunological and productive consequences of HS and evaluated mitigation strategies. RESULTS: The reviewed studies demonstrate that HS reduces feed intake by approximately 10%-30%, suppresses body weight gain and feed efficiency and increases mortality, with severity depending on temperature, humidity and broiler genotype. HS disrupts carbohydrate, protein and lipid metabolism; induces acid-base imbalance and oxidative stress; compromises intestinal barrier integrity; alters gut microbiota; suppresses immune function; and reduces meat quality. Nutritional interventions, including dietary electrolyte balance, antioxidants, vitamins, selenium, zinc, phytogenic compounds, probiotics, betaine and optimised feeding strategies, environmental management and genetic approaches, including naked-neck and frizzle genes, can partially alleviate these adverse effects. However, inconsistencies among studies persist because of differences in broiler strains, environmental conditions, dietary formulations and experimental protocols. CONCLUSION: HS substantially compromises broiler health, welfare, productivity and meat quality. Nutritional, environmental and genetic approaches can partially mitigate its adverse effects; however, further research is needed to improve broiler resilience under increasingly HS conditions.

Animals↗

PubMed2001

The effect of discontinuing the use of antimicrobial growth promoters on the productivity in the Danish broiler production.

On 15 February 1998, the Danish poultry industry voluntarily decided to discontinue the use of all antimicrobial growth promoters (AGPs). To investigate how the removal of AGPs influenced the broiler productivity in Denmark, data from 6815 flocks collected from November 1995 to July 1999 by the Danish Poultry Council were analysed. The three flock parameters were: kilogram broilers produced per square meter (per rotation), feed-conversion ratio (total kilogram feed used per rotation/total kilogram live weight per rotation) and total percent dead broilers ((number of dead broilers during the rotation/number of broilers put in the house per rotation)x100). Data were analysed using a mixed model, allowing the correlation structures in the data to be taken into account. The analyses showed that kilogram broilers produced per square meter and percent dead broilers in total were not affected by the discontinued use of AGPs. However, the feed-conversion ratio increased marginally 0.016 kg/kg and has remained at this level throughout the rest of the study period.

Animals↗

PubMed2000

The behaviour of broiler chickens and its modification by lameness.

The behaviour of six replicates of broilers obtained from commercial farms, fed ad-libitum and housed on 23-h light:1-h dark schedule at 20 lx was observed using scan sampling. Comparisons were made between sound birds and those of varying degrees of lameness between 39 and 49 days of age. Sound broilers averaged 76% of their time lying and this increased significantly to 86% in lame birds (gait score 3). Lying also increased with age. Although sound broilers spent only a minor part of the day on their feet, they spent significantly more time standing idle (7%), standing preening (3.5%) and standing eating (4.7%) than lame birds. Walking declined with age, but occupied an average 3.3% of the time of a slaughter-weight broiler. Again, lameness significantly reduced this to a minimal 1.5% in the worst affected birds. Sound birds predominantly chose the usual standing posture for eating, whereas, lame birds lay down to eat for almost half their feeding time. Detailed observations using video records revealed that lameness altered the feeding strategy of broilers. Whereas sound birds fed over 50 times in 24 h, the number of visits to the feeder was reduced with increasing lameness to an average of around 30 in the lamest broilers. However, meal duration was adjusted to give no overall differences in time spent feeding per day. Time spent drinking was also the same for all birds, averaging 3% of the day. The alterations of the time budget, in particular the reductions in activities performed whilst standing, and the different feeding strategies adopted, are consistent with lameness imposing a cost on the affected broilers to the detriment of their welfare.

Journal Article↗

PubMed2000

Comparison of antimicrobial resistance phenotypes and resistance genes in Enterococcus faecalis and Enterococcus faecium from humans in the community, broilers, and pigs in Denmark.

Enterococcus faecalis and E. faecium isolated from humans in the community (98 and 65 isolates), broilers (126 and 122), and pigs (102 and 88) during 1998 were tested for susceptibility to 12 different antimicrobial agents and for the presence of selected genes encoding resistance using PCR. Furthermore, the presence of vancomycin resistant enterococci was examined in 38 human stool samples using selective enrichment. Widespread resistance to chloramphenicol, macrolides, kanamycin, streptomycin, and tetracycline was found among isolates from all three sources. All E. faecium isolates from humans and pigs were susceptible to avilamycin, whereas 35% of isolates from broilers were resistant. All E. faecium isolates from humans were susceptible to vancomycin, whereas 10% and 17% of isolates from broilers and pigs, respectively, were resistant. A vancomycin resistant E. faecium isolate was found in one of the 38 human fecal samples examined using selective enrichment. All vancomycin resistant isolates contained the vanA gene, all chloramphenicol resistant isolates the cat(pIP501) gene, and all five gentamicin resistant isolates the aac6-aph2 gene. Sixty-one (85%) of 72 erythromycin resistant E. faecalis examined and 57 (90%) of 63 erythromycin resistant E. faecium isolates examined contained ermB. Forty (91%) of the kanamycin resistant E. faecalis and 18 (72%) of the kanamycin resistant E. faecium isolates contained aphA3. The tet(M) gene was found in 95% of the tetracycline resistant E. faecalis and E. faecium isolates of human and animal origin, examined. tet(K) was not observed, whereas tet(L) was detected in 17% of tetracycline resistant E. faecalis isolates and in 16% of the E. faecium isolates. tet(O) was not detected in any of the isolates from pigs, but was observed in 38% of E. faecalis isolates from broilers, in two E. faecalis isolates from humans and in three E. faecium isolates from broilers. tet(S) was not detected among isolates from animals, but was observed in 31% of E. faecalis and one E. faecium isolate from humans. This study showed a frequent occurrence of antimicrobial resistance and the presence of selected resistance genes in E. faecalis and E. faecium isolated from humans, broilers and pigs. Differences in the occurrence of resistance and tetracycline resistance genes were observed among isolates from the different sources. However, similar resistance patterns and resistance genes were detected frequently indicating that transmission of resistant enterococci or resistance genes takes place between humans, broilers, and pigs.

Animals↗

PubMed2000

Cottonseed with a high (+)- to (-)-gossypol enantiomer ratio favorable to broiler production.

This study was designed to evaluate the relative toxicity of (+)- and (-)-gossypol enantiomers in 0-3-week-old broilers. Treatments consisted of broiler starter diets formulated with either a glandless, which did not contain gossypol, a commercial glanded [62. 2% (+)-gossypol], or a glanded moco [83.2% (+)-gossypol] crushed cottonseed (CCS) (six replicates/treatment) plus a soybean meal negative control. Glandless cottonseed was mixed with the moco cottonseed (2.4% free gossypol) so that both the commercial glanded and moco glanded cottonseeds contained equivalent concentrations of free gossypol (2.0%). The cottonseed treatments were added at 5 and 10% of the diet. Body weights and feed conversions were determined weekly. Body weights and feed-to-gain ratios of broilers fed 5 and 10% glandless CCS and 5% moco CCS were not significantly different. Broilers receiving 10% commercial glanded CCS weighed significantly less than those subjected to all other treatments. Feed-to-gain ratios were significantly higher for broilers receiving 10% commercial glanded and 10% moco CCS as compared to 5% moco and glandless CCS, 10% glandless CCS, and control. Relative liver weights of birds receiving 10% moco CCS were significantly less than those of birds receiving 10% commercial CCS. The data clearly showed that broilers fed moco CCS containing a relatively high (+)- to (-)-gossypol enantiomer ratio performed better than broilers receiving commercial CCS with a lower (+)- to (-)-gossypol enantiomer ratio.

Animal Feed↗

PubMed2001

Pharmacokinetics of sarafloxacin in pigs and broilers following intravenous, intramuscular, and oral single-dose applications.

Pharmacokinetics of sarafloxacin, a fluoroquinolone antibiotic, was determined in pigs and broilers after intravenous (i.v.), intramuscular (i.m.), or oral (p.o.) administration at a single dose of 5 (pigs) or 10 mg/kg (broilers). Plasma concentration profiles were analysed by a noncompartmental pharmacokinetic method. Following i.v., i.m. and p.o. doses, the elimination half-lives (t1/2beta) were 3.37 +/- 0.46, 4.66 +/- 1.34, 7.20 +/- 1.92 (pigs) and 2.53 +/- 0.82, 6.81 +/- 2.04, 3.89 +/- 1.19 h (broilers), respectively. After i.m. and p.o. doses, bioavailabilities (F) were 81.8 +/- 9.8 and 42.6 +/- 8.2% (pigs) and 72.1 +/- 8.1 and 59.6 +/- 13.8% (broilers), respectively. Steady-state distribution volumes (Vd(ss)) of 1.92 +/- 0.27 and 3.40 +/- 1.26 L/kg and total body clearances (ClB) of 0.51 +/- 0.03 and 1.20 +/- 0.20 L/kg/h were determined in pigs and broilers, respectively. Areas under the curve (AUC), mean residence times (MRT), and mean absorption times (MAT) were also determined. Sarafloxacin was demonstrated to be more rapidly absorbed, more extensively distributed, and more quickly eliminated in broilers than in pigs. Based on the single-dose pharmacokinetic parameters determined, multiple dosage regimens were recommended as: a dosage of 10 mg/kg given intramuscularly every 12 h in pigs, or administered orally every 8 h in broilers, can maintain effective plasma concentrations with bacteria infections, in which MIC90 are <0.25 microg/mL.

Administration, Oral↗

PubMed2001

Prevalence and antimicrobial susceptibility of thermophilic Campylobacter in organic and conventional broiler flocks.

AIMS: To determine the flock prevalence and to estimate the within flock prevalence of Campylobacter in broiler flocks from different rearing systems, and to determine the antimicrobial susceptibility of Campylobacter isolates to selected antimicrobial substances. METHODS AND RESULTS: One hundred and sixty broiler flocks originating from organic, conventional and extensive indoor production farms were investigated for the presence of Campylobacter at the time of slaughter. Campylobacter isolates from a subsample of positive flocks were subjected to susceptibility testing. Campylobacter spp. were isolated from 100% of organic broiler flocks, from 36.7% of conventional broiler flocks and from 49.2% of extensive indoor broiler flocks. Six of 62 Campylobacter isolates were resistant to one or more of the antimicrobials tested. CONCLUSION: These results indicate that the special characteristics of organic broiler production provide a high prevalence of Campylobacter-positive flocks. Antimicrobial resistance was scarce among Campylobacter isolates from all rearing systems. SIGNIFICANCE AND IMPACT OF THE STUDY: Organic broiler flocks constitute a strong potential for introduction of Campylobacter to the processing line upon arrival at slaughter.

Abattoirs↗

PubMed2005

Concentrations of cholesterol oxidation products in raw, heat-processed and frozen-stored meat of broiler chickens fed diets differing in the type of fat and vitamin E concentrations.

The present study was performed to investigate the effect of dietary fat and vitamin E on concentrations of cholesterol oxidation products (COP) in broiler muscle. A total of 144 1-d-old broiler chicks were fed diets with either palm oil, soyabean oil or linseed oil and vitamin E concentrations of 20, 40 or 200 mg/kg for 35 d. COP concentrations were analysed in raw, heat-processed (180 degrees C, 20 min) and frozen-stored (-20 degrees C, 6 months) breast and thigh muscles. COP concentrations were influenced by dietary vitamin E concentration, dietary fat, treatment and type of muscle (P<0.001). Increasing the dietary vitamin E concentration generally reduced the concentration of COP. This effect was strongest in broilers fed linseed oil and weakest in broilers fed palm oil; the effect of vitamin E was also stronger in heated muscles than in raw or frozen-stored muscles. Moreover, the concentration of COP in thigh muscle was more strongly influenced by dietary vitamin E than that in breast muscle. COP concentrations in muscles were on average highest in broilers fed linseed oil and lowest in broilers fed palm oil, but the effect of the dietary fat also depended on the vitamin E concentration, the treatment and the type of muscle. In conclusion, our study shows that dietary fat and vitamin E influence the concentrations of total COP in broiler muscle. However, the effects of these factors were not only influenced by interactions between each other, but also depended on the treatment of the muscle and the type of muscle.

Animals↗

PubMed2004

Effects of dietary L-carnitine and coenzyme Q10 supplementation on performance and ascites mortality of broilers.

The study was conducted to determine the effects of dietary L-carnitine and coenzyme Q10 (CoQ10) supplementation on growth performance and ascites mortality of broilers. A 3 x 3 factorial arrangement was employed with three levels (0, 75 and 150 mg/kg) of L-carnitine and three levels of CoQ10 (0, 20 and 40 mg/kg) supplementation during the experiment. Five hundred and forty one-day-old Arbor Acre male broiler chicks were randomly allocated into nine groups with six replicates each. All birds were fed with the basal diets from day 1 to 7 and changed to the experimental diets from day 8. During day 15 to 21 all the birds were exposed to low ambient temperature (15-18 degrees C) to induce ascites. The results showed that under this condition, growth performance of broilers were not significantly affected by CoQ10 or L-carnitine + CoQ10 supplementation during week 0-3 and 0-6, but body weight gain (BWG) of broilers was significantly reduced by 150 mg/ kg L-carnitine during week 0-6. Packed cell volume (PCV) of broilers was significantly decreased by L-carnitine and L-carnitine + CoQ10 supplementation (P < 0.05). Erythrocyte osmotic fragility (EOF), ascites heart index (AHI) and ascites mortality of broilers were significantly decreased by L-carnitine, CoQ10 and L-carnitine + CoQ10 supplementation. Though no significant changes were observed in total antioxidative capability (T-AOC), total superoxide dismutase (T-SOD) was increased by L-carnitine, CoQ10 and L-carnitine + CoQ10 supplementation (P < 0.05). Malonaldehyde (MDA) content was significantly decreased by CoQ10 and L-carnitine + CoQ10 supplementation. The results indicate that dietary L-carnitine and CoQ10 supplementation reduce ascites mortality of broilers; the reason may be partially associated with their antioxidative effects.

Animal Feed↗

PubMed2002

Effects of restricted feeding on physiological stress parameters in growing broiler breeders.

1. In previous studies, a lack of agreement in measurements of plasma corticosterone concentrations and heterophil:lymphocyte (H/L) ratio as physiological indices of stress, caused by hunger and frustration in restricted-fed broiler breeders, was observed. It could be suggested that the differences between previous studies were caused by differences in duration of restriction and time of the day of the measurements. Therefore, in the present study the plasma corticosterone concentration and the H/L ratio were again determined in restricted- and ad libitum-fed growing broiler breeders, taking possible causes of disagreement between previous studies into account. In addition, we measured the daily rhythm in body temperature and heart rate, and the corticosterone responses to an acute stressor as physiological indices of stress. 2. Female broiler breeders (64 per treatment, housed in groups of 4 birds) were used in the experiment. Behaviour, baseline plasma corticosterone concentrations and H/L ratio were determined at 21 d of age (immediately after the start of food restriction), and at 42 and 63 d of age. Body temperature, heart rate and activity were measured by radiotelemetry for 36 h at 49 and 70 d of age. In addition, the plasma corticosterone response to acute stress (5 min manual restraint) was measured at 77 or 78 d of age. 3. Restricted broiler breeders had higher plasma corticosterone concentrations at 42 and 63 d of age, but no differences in H/L. ratio were found between restricted birds and unrestricted control birds. Restricted broiler breeders had a higher corticosterone response to 5 min manual restraint than unrestricted birds. Restricted birds displayed a clear day-night rhythm in body temperature, heart rate and activity whereas such a rhythm was blunted in ad libitum-fed birds. 4. It is discussed that some physiological differences (plasma corticosterone concentrations, body temperature and heart rate) between ad libitum-fed and restricted broiler breeders may have been caused by differences in metabolic rate as well as by differences in the level of stress. It is concluded that a combination of behavioural measurements and a wide range of physiological parameters should be used for the assessment of stress in growing broiler breeders.

Animal Feed↗