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PubMed2002

Effect of administration of Lactobacillus crispatus, Clostridium lactatifermentans and dietary lactose on the development of the normal microflora and volatile fatty acids in the caeca of broiler chicks.

1. Lactobacillus crispatus and Clostridium lactatifermentans, both isolated from the caeca of chickens, grown together in an in vitro model system are able to ferment lactose to acetate and propionate. In this study, the capabilities of these organisms were studied in vivo. 2. The effect on concentrations of volatile fatty acids and lactate, together with the development of some bacterial groups in the caeca of chicks, was studied after oral inoculation with L. crispatus and C. lactatifermentans together with dietary lactose. For this purpose, chicks were divided into 4 groups: (i) control group, (ii) dietary lactose, (iii) L. crispatus and C. lactatifermentans, and (iv) dietary lactose together with L. crispitaus and C. lactatifermentans. 3. In general, concentrations of (undissociated) volatile fatty acids in the caeca were not significantly different in broilers receiving both bacteria and dietary lactose compared with control broilers. Concentrations of lactate in the caeca of 14-d-old broilers treated with any of the three treatments were significantly higher than in the caeca of control broilers. 4. This indicates that L. crispatus or other lactate-producing organisms were responsible for the elevated concentrations of lactic acid. Clostridium lactatifermentans has probably not colonised the caeca sufficiently to ferment this lactate further to acetate and propionate. 5. Numbers of Enterobacteriaceae and enterococci in the caeca of broilers receiving both bacteria and dietary lactose were not different from control broilers. 6. We conclude from these results that under the conditions applied in this study a mixture of L. crispatus and C. lactatifermentans with dietary lactose was able to increase lactate concentrations but was unable to increase concentrates of acetate and propionate in the caeca of broiler chicks.

Animals↗

PubMed2003

Effects of Lactobacillus cultures on growth performance, abdominal fat deposition, serum lipids and weight of organs of broiler chickens.

1. The effects of a mixture of 12 Lactobacillus strains (LC) on the growth performance, abdominal fat deposition, serum lipids and weight of organs of broiler chickens were studied from 1 to 42 d of age. 2. One hundred and thirty-six 1-d-old male broiler chicks were assigned at random to two dietary treatments: a basal diet (control), and a basal diet with 0.1% LC. 3. The supplementation of LC in broiler diets improved the body weight gain and feed conversion rate from 1 to 42 d of age and was effective in reducing abdominal fat deposition but only after 28 d of age. 4. The LC diets reduced serum total cholesterol, low density lipoprotein (LDL) cholesterol and triglycerides in broilers from 21 to 42 d of age. However, there was no significant difference in serum high density lipoprotein (HDL) cholesterol between control and LC-fed broilers. There was also no significant difference in the weights of organs of control and LC-fed broilers. 5. The results indicated that the mixture of 12 Lactobacillus strains have a hypolipidaemic effect on broilers.

Abdomen↗

PubMed2006

Effect of different non-chloride sodium sources on the performance of heat-stressed broiler chickens.

1. One hundred and eighty 1-d-old broiler chicks were used to evaluate the effect upon broiler performance during severely hot summer months of three different sodium salts: sodium bicarbonate (NaHCO3), sodium carbonate (Na2CO3) and sodium sulphate (Na2SO4), in starter and finisher diets having an identical electrolyte balance (DEB) of 250 mEq/kg. 2. The non-chloride sodium salts were added to contribute the same amount of sodium and were substituted at the expense of builder's sand in the basal diets containing common salt (NaCl) as Na and Cl source. 3. Each diet was fed to three experimental units having 15 chicks each until 42 d of age. Severe heat-stress conditions, maintained in the rearing room, were indicated by high average weekly room temperature (minimum 29.3 degrees C; maximum 38.0 degrees C). 4. Diets containing sodium salts gave better body weight gain, feed intake and feed to gain ratio than the control diet. Sodium salts also enhanced water intake as well as water to feed intake ratio. This effect was more pronounced in broilers fed NaHCO3 supplement (with NaCl in the basal diets). 5. The increased water intake resulted in lower body temperature in heat-stressed birds fed NaHCO3 supplemented diet than in birds fed other sodium salts. A lower mortality rate was noted with NaHCO3 (15.15%), Na2CO3 (13.64%) and Na2SO4 (15.15%) supplements than with the control (33.33%) treatment. 6. Better carcase and parts yield were observed in sodium supplemented broilers. Sodium salts reduced the alkalotic pH and enhanced the blood sodium content, which ultimately improved the blood electrolyte balance and overall performance of heat-stressed broilers. 7. Supplementing broiler diets with sodium salts improved the live performance of heat-stressed broilers and better productive performance was noted with NaHCO3 than other sodium supplements.

Animals↗

PubMed1995

A simple steady state model of the distribution of vertical temperature in broiler houses without internal air circulation.

1. The vertical temperature profile in a broiler house depends on several factors: ground temperature, heat production by the birds, heating of litter by resting birds, stratification and radiation, microbial heat production in the litter, moisture loss from litter and natural convection around the birds. The effect on the vertical temperature profile is calculated for each factor and the effects are finally combined to estimate vertical temperature distribution. 2. The vertical temperature profile in a commercial broiler house depends on the age of the birds. Influential factors for young broilers are ground temperature and stratification. For older broilers, influential factors are floor construction and ground-water table, heat production of broilers and litter, the behaviour of the broilers and air circulation in the house. 3. Temperatures in the living zone can differ appreciably, by a maximum of about 4 degrees C, from mean house temperature. 4. The velocity of air induced by the heat production of the broilers is about 5 cm/s. This provides good air mixing in the living zone.

Air Movements↗

PubMed1995

Contribution of oligosaccharide and polysaccharide digestion, and excreta losses of lactic acid and short chain fatty acids, to dietary metabolisable energy values in broiler chickens and adult cockerels.

1. Two experiments were conducted, using both adult cockerels from a layer strain and 3-week-old broiler chickens. In the first experiment, one of the 2 diets investigated was composed mainly of maize and soyabean meals, the other one containing the latter ingredients diluted with 475 g/kg mature pea seeds. For these 2 diets, the apparent metabolisable energy values corrected to 0 nitrogen retention (AMEn) were derived, together with the apparent digestibilities of nitrogen, amino acids, total lipids, starch, individual oligosaccharides, and non-starch polysaccharides (NSP). Excretions of lactic acid and short chain fatty acids (SCFA) were also determined. 2. In the first experiment, the mean apparent digestibilities of starch, lipids, total amino acids, NSP, sucrose and alpha-galacto-oligosaccharides in adult cockerels were 0.946, 0.785, 0.835, 0.045, 0.99 and 0.99, respectively. In broiler chickens, they were 0.938, 0.675, 0.830, -0.016, 0.988 and 0.867, respectively. The bird type effects were significant (P < 0.05) for the digestibilities of starch, lipids, NSP (for the maize-soyabean meal diet, only) and alpha-galacto-oligosaccharides. Broiler chickens excreted a mean of 11.032 g organic acids/kg diet against 4.190 in adult cockerels (P < 0.001). These digestibility measurements enabled the contribution made by each dietary component to the AMEn value of the diets to be calculated. AMEn values were lower in broiler chickens than in adult cockerels, with on average 0.8 MJ/kg dry matter difference resulting from bird type. This difference was accounted for by differences between bird types in energy supplied by lipids (34.0%), starch (7.5%), alpha-galacto-oligosaccharides (8.7%), NSP (14.2%), and in energy losses from lactic acid excretion (16.4% of the difference in AMEn between bird types). 3. In the second experiment 2 diets were studied, consisting of a basal and the basal diluted with 30 g/kg lactose (a fermentable sugar in chickens) and 12 g/kg of a water-soluble gel-forming component containing 50% polygalacturonic acids. Lactose digestibilities reached 0.928 and 0.712 in adult cockerels and chickens, respectively. The digestibilities of the water-soluble polygalacturonic acids were similar in cockerels and broiler chickens, with a mean value of 0.672. Figures similar to those of the first experiment were found in the comparison between cockerels and broiler chickens, for the AMEn values of diets, the digestibilities of starch and lipids and the excretion of lactic acid. Broiler chickens excreted 4.580 g lactic acid/kg dry food intake, compared with 0.740 g in the adult.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗

PubMed2001

Influences of wet feeding and supplementation with ascorbic acid on performance and carcass composition of broiler chicks exposed to a high ambient temperature.

In two experiments was investigated whether feeding with an air-dry feed mixed with different amounts of water and/or supplemental ascorbic acid affect performance and carcass compositions of broilers exposed to a high ambient temperature (35 to 37 degrees C for 8 h/d and thermoneutral for 16 h/d). In the first trial, 64 one-week-old male broiler chicks were fed ad libitum in four dietary treatment groups for a 6-week period. Experimental mash diets were prepared by mixing a maize-soybean based standard broiler starter or finisher with tap water in the ratios of 0.0:1.0, 0.5:1.0, 1.0:1.0 and 1.5:1.0 (water:air-dry feed, w/w). More water in the diet increased BWG, DMI, abdominal fat and carcass weight, carcass CP, crude fat, but it deteriorated DM conversion efficiency. In the second experiment, 64 one-week-old male broiler chicks were given air-dry or wet (water:feed, 1.5:1) starter or finisher diets without or with ascorbic acid supplementation (0 and 250 mg/kg air-dry feed, resp.) ad libitum for a 6-week period. Ascorbic acid supplementation increased BWG, carcass weight and carcass CP significantly, while reducing carcass crude fat content. However, feeding broilers with a diet mixed with water in a ratio of 1.5:1.0 increased BWG, DMI, carcass weight and carcass lipid markedly, but deteriorated DM conversion efficiency. There was also a significant interaction between ascorbic acid and wet feeding, whereby ascorbic acid supplementation induced a significant reduction in carcass lipid contents of broilers fed on air-dry diets but not on wet diets. It is concluded that wet feeding, especially an addition of 150% water to produce a porridge like consistency, improved growth performance by increasing fat, ash and protein deposition in the body, while reducing DM conversion efficiency. It is also concluded that under heat stress supplemental ascorbic acid in air-dry diets stimulates broiler performance but not in wet diets.

Adipose Tissue↗

PubMed2026

Narasin used as a feed additive in conventional rearing of broilers can co-select for vancomycin-resistant Enterococcus faecium through the NarAB ionophore resistance mechanisms.

OBJECTIVES: To investigate the role of the NarAB resistance mechanism in the selection of vancomycin-resistant Enterococcus faecium (VREfm) and assess the impact of ionophore feed additives, particularly narasin, on the emergence of VREfm in broiler chickens. MATERIALS AND METHODS: Three isogenic E. faecium strains with different antimicrobial resistance determinants were created by mutagenesis and conjugation and used in a controlled animal experiment. Ross 308 broiler chickens were inoculated with either a rifampicin-resistant, a rifampicin- and vancomycin-resistant or a rifampicin-, vancomycin- and narasin-resistant strain and fed diets supplemented with selected ionophores. Bacterial populations were analysed on selective Slanetz and Bartley agar to determine the presence and selection of VREfm and other vancomycin-resistant species. Bacterial inoculation strains and isolates were whole genome sequenced for species identification and to identify genetic resistance mechanisms. RESULTS: Narasin was shown to select for VREfm in broilers, with NarAB being essential for co-selection. Intrinsically vancomycin-resistant Pediococcus acidilactici and Enterococcus gallinarum were identified as part of the broilers' vancomycin-resistant resident microbiota. Notably, among the P. acidilactici isolates that were susceptibility tested, strains resistant to both vancomycin and narasin were only found in broilers fed narasin, supporting that narasin promotes the growth of narasin-resistant populations. CONCLUSION: Narasin use in broiler feed can co-select for vancomycin-resistant bacteria, including VREfm, through the NarAB mechanism. These findings emphasize the concerns associated with the use of particular ionophores in poultry and suggest that vancomycin and narasin resistance may be more widespread in the broiler microbiota than previously recognized. Further research is needed to understand the implications for antimicrobial resistance and human health.

Animals↗

PubMed1997

Effect of sucrose thermal oligosaccharide caramel, dietary vitamin-mineral level, and brooding temperature on growth and intestinal bacterial populations of broiler chickens.

Two experiments were conducted to determine the effect of sucrose thermal oligosaccharide caramel (STOC) and dietary vitamin-mineral (V/M) level on growth performance and intestinal microflora of broiler chickens. In Experiment 1, Peterson x Arbor Acres male broilers (n = 384) were randomly allocated into four groups that were fed either the control diet or diets containing the antibiotic virginiamycin (11 mg/kg), 3.7% STOC or 7.5% STOC for 4 wk at brooding temperatures of 32 to 29.7 C. Weight gains for broilers in Experiment 1 were greater (P < 0.001) for birds fed STOC diets, with weight gains of 763, 822, 1,124, and 1,080 g for birds on the control, antibiotic, 3.7% STOC, and 7.5% STOC diets, respectively. Feed intake and feed conversion by birds fed STOC diets were also significantly improved. Cecal bifidobacterial numbers were increased (P < 0.03) over the control diet with numbers being 5.98, 6.99, 7.47, and 7.39 log10 cfu/g cecal DM, respectively. In Experiment 2, Peterson x Hubbard male broilers (n = 384) were used in a 2 x 2 x 2 factorial arrangement with two levels of V/M premix (0.5 or 1% of the diet), two levels of STOC (0 or 3.5% of the diet), and two brooding temperatures, normal (32 to 23.6 C) or high (32 to 29.7 C) for 4 wk. Feeding the STOC diet improved (P < 0.05) weight gain, feed intake, and feed conversion of broilers. The effect of STOC on animal performance was less evident when broilers were fed twice the NRC recommended levels of V/M. Feeding the STOC diets resulted in a significantly greater increase in weight gain at high brooding temperatures than at normal brooding temperatures. There was also a reduction (P < 0.05) in numbers of total aerobes and coliforms in the ceca of birds fed diets containing STOC. Feeding STOC has potential to improve growth performance of broiler chickens.

Actinomycetales Infections↗

PubMed1997

Performance of naked neck and normal broilers in hot, warm, and temperate climates.

Chickens suffer at high ambient temperatures because their feather coverage hinders internal heat dissipation. Naked neck broilers (Na/na) and their normally feathered sibs (na/na) were evaluated in three natural climates. Three experiments were conducted in Turkey, during the summer in the extremely hot region of Adana (Ad-Sm), and in the moderate region of Izmir during the spring (Iz-Sp) and summer (Iz-Sm), always following the same experimental protocol. Ambient temperatures averaged 19, 28, and 32 C in Iz-Sp, Iz-Sm, and Ad-Sm, respectively. About 300 birds per genotype were included in each experiment. Feather weight was lower by about 20% in Na/na broilers than in na/na ones, independent of climate, sex, and age (6 or 7 wk). The Na/na broilers exhibited higher breast weight in all cases, from 2.5 to 10.9% higher than their na/na counterparts. Body weight gain from 4 to 7 wk (BWG4-7) clearly reflected the differences in ambient temperature among climates. The effect of the Na/na genotype on BWG4-7 interacted with climate and sex. In the hottest climate (Ad-Sm), both male and female Na/na broilers exhibited a highly significant advantage over their na/na counterparts. In the more moderate climate (Iz-Sm), the Na/na genotype exhibited superior growth only among males, and the magnitude of this advantage was lower than in Ad-Sm. In the cool temperate climate (Iz-Sp), BWG4-7 and BW7 (BW at 7 wk) means were similar for both genotypes. In Iz-Sp, feed efficiency (FE) of the Na/na birds was lower by about 4%, but in the two summer climates (Iz-Sm and Ad-Sm), FE of the Na/na birds was about 9% higher than that of their na/na counterparts. Body temperature was lower in the Na/na broilers than in their na/na counterparts; in all cases, the difference increasing with ambient temperature. The results indicate that the reduction in feather coverage provided relative heat tolerance, and therefore, under hot climates the Na/na broiler were superior to their normally feathered counterparts. It is concluded that naked neck broilers should be preferred in hot climates.

Animals↗

PubMed1998

Incidence of Campylobacter in crops of preharvest market-age broiler chickens.

Previous research has identified cecal and intestinal contents as sources for Campylobacter contamination of broiler carcasses in the processing plant. During the present study, we evaluated the crop contents of preharvest market-age broilers as a potential reservoir of field-derived Campylobacter in the processing plant. Crops were collected aseptically from 40 randomly selected market-age broilers in each of nine commercial broiler flocks. Ceca were collected from broilers in six of the same flocks for comparison with the crop samples. The presence of Campylobacter in the crops and ceca was determined by enrichment culture in Bolton broth followed by culture on Campy-Ceflex plates. Campylobacter was isolated from the crop contents of broilers in seven of the nine flocks and from the cecal contents in three of six flocks. The incidence of Campylobacter-positive crop samples among all birds evaluated (224/359; 62%) was significantly higher (P < 0.001) than the number of positive cecal samples (9/240; 4%). The results indicate that the incidence of Campylobacter contamination of crop contents may exceed that of the cecal contents by as much as 37-fold in some broiler flocks, and may represent a critical preprocessing control point in reducing Campylobacter entry into the processing plant.

Animals↗

PubMed1999

The effects of the naked neck (Na) and frizzle (F) genes on growth and meat yield of broilers and their interactions with ambient temperatures and potential growth rate.

High ambient temperatures (AT) decrease the growth of broilers because of difficulty in dissipating heat through the feather coverage. Broilers selected for higher growth rate eat more and generate more heat per unit of time; hence, they may become more sensitive to high AT. Reduced feather coverage, either by decreased number or by modified shape, may help birds to dissipate internal heat more efficiently. Two broiler stocks were studied; each was segregated for four genotypes with regard to the genes for naked neck (Na) and frizzled feathers (F): heterozygous naked neck (Na/na f/f), heterozygous frizzle (na/na F/f), double heterozygous (Na/na F/f), and normally feathered (na/na f/f). One stock had a high growth rate (GR) similar to current commercial broilers, whereas the second stock had a lower GR. Birds of each stock, genotype, and sex were reared under constant standard AT (24 C) or high AT (32 C). Body weight at 4 and 7 wk, weight gain (WG) from 4 to 7 wk, breast meat yield, and feather weight were recorded. Reduction in WG from 4 to 7 wk because of high AT was greater in high-GR birds than in low-GR birds, but, in both stocks, the high AT effect was greater on normally feathered birds than on the other three genotypes. AT 32 C, in low- and high-GR stocks, the F allele increased WG from 4 to 7 wk and increased the BW at 7 wk of fully feathered (na/na) broilers but had no effect on meat yield. The effects of the Na allele were similar to or greater than those of the F allele. The Na allele did not affect breast meat yield of low-GR broilers but increased it significantly in high-GR broilers. Combining the two allles resulted in an additive effect, which was more pronounced in the high-GR stock.

Alleles↗

PubMed1999

Renal responses of normal and preascitic broilers to systemic hypotension induced by unilateral pulmonary artery occlusion.

During the pathophysiological progression of pulmonary hypertension syndrome (PHS; ascites), broilers concurrently develop systemic hypotension (low mean systemic arterial pressure) that may initiate renal retention of water and solute, contributing to fluid accumulation in the abdominal cavity (ascites). In male Single Comb White Leghorns, glomerular filtration is autoregulated over a systemic arterial pressure range of 110 to 60 mm Hg, and corresponding reductions in urine flow are attributed to a phenomenon known as pressure natriuresis. Acute unilateral pulmonary artery occlusion was used in the present study to reduce systemic arterial pressure toward the lower autoregulatory limit for glomerular filtration, and to evaluate kidney function in normal and preascitic broilers. Preascitic broilers characteristically exhibited lower (P < or = 0.05) values for mean systemic arterial pressure (91 vs 100 mm Hg) and percentage saturation of hemoglobin with oxygen (73 vs 84%), higher hematocrits (35 vs 30%), heavier right ventricles (3.44 vs 2.32 g), and higher right:total ventricular weight ratios (0.32 vs 0.24) than normal broilers. Body weights (2,445 vs 2,429 g, respectively), left ventricle plus septum weights (7.16 vs 7.19 g), and heart rates (349 vs 341 beats/min) were similar. Preascitic broilers exhibited larger (P < or = 0.05) dependent reductions in glomerular filtration, urine flow, osmolal clearance, and solute excretion and had a higher free water clearance than normal broilers in response to pulmonary artery occlusion. The differences observed between normal and preascitic broilers demonstrate that systemic hypotension can trigger renal mechanisms contributing to fluid and solute retention during development of PHS.

Animals↗

PubMed2000

Effect of delayed placement on the incidence of Campylobacter jejuni in broiler chickens.

An experiment was conducted with broiler chickens to evaluate the effect of delayed placement on reused litter and the isolation of Campylobacter jejuni. The experiment also assessed the presence of C. jejuni in the crop following feed withdrawal periods in cages vs floor environments. Trial 1 utilized 320 female broiler chicks obtained from a commercial hatchery. The chicks were randomly placed into the following experimental groups that were replicated four times with 20 chicks per pen: 1) 0-h, 2) 24-h, 3) 48-h, and 4) 72-h delayed placement. Fecal samples were collected via the cloaca at 7, 14, 21, and 28 d of age; enriched in Bolton broth; and plated onto BBL agar. Campylobacter jejuni was isolated at 1 wk of age in the 48- and 72-h experimental groups but did not differ significantly from the others. Sampling results at 14 d of age showed that 63, 68, 73, and 80% of chicks were positive for the 0-, 24-, 48-, and 72-h treatments, respectively. At 28 d of age, 100% of all chicks sampled tested positive. In Trial 2, 60 market age broilers were evaluated for the presence of C. jejuni in the crop by subjecting them to 0-, 4-, 8-, 12-, and 16-h feed withdrawal times on litter or in wire cages. Crops were collected aseptically from the broilers, stomached, enriched in Bolton broth, and then plated on BBL agar. There were no significant (P < 0.05) differences between cage and floor withdrawal times for the presence of C. jejuni in the crop samples of broilers; however, there were significant differences in the length of withdrawal on the presence of C. jejuni. Collectively, these results suggested that the isolation of C. jejuni occurred earlier in broilers that were subjected to delayed placement on reused litter and that extended feed withdrawal times in cages or on litter may increase the possibility that the crop of broilers may contain a higher isolation rate of C. jejuni.

Aging↗

PubMed2000

Infection and immunity in broiler chicken breeders vaccinated with a temperature-sensitive mutant of Mycoplasma gallisepticum and impact on performance of offspring.

A comparison of infection and immunity to Mycoplasma gallisepticum (MG) in broiler chicken breeders vaccinated with a temperature-sensitive mutant of MG versus nonvaccinated chickens, and the impact on the performance of their offspring was conducted. Infection and immunity in breeders were assessed by culture and enzyme-linked immunoassay, respectively. However, performance in their offspring was assessed by studying MG infection in embryos, occurrence of infection titers to MG in relation to mortality, and feed conversion in the broilers. Five out of 10 broiler chicken breeder flocks raised on the same multiple-age farm with a long history of mycoplasmosis were vaccinated intraocularly once with a temperature-sensitive MG mutant vaccine (ts-11) at an average age of 7.5 wk; another five breeder flocks were left as unvaccinated controls exposed to field MG. The average recoveries of ts-11 organisms from tracheas and infraorbital sinuses of 41-wk-old vaccinates were 88 and 84%, respectively. No field MG organisms were recovered from vaccinates between 15 and 41 wk of age. The recovery of field MG organisms from tracheas and sinuses of nonvaccinated chickens increased to an average of 100% at 41 wk of age. A significant decrease (P < 0.05) in the average percentage of MG-seroconverted breeders occurred in ts-11-vaccinated flocks in comparison with nonvaccinated, MG-infected flocks at 15, 20, 23, 29, 32, 36, and 41 wk of age. The average infection prevalence by MG in the vitelline membrane of 7-d-old embryos produced by the five unvaccinated breeder flocks peaked at 79% when their respective hatching eggs were collected at 36 wk of breeder's age. Embryos of ts-11-vaccinated flocks had zero prevalence of MG infection at all times between 29 and 57 wk of breeder's age. Seroconversion to MG (average of 17.7%) at 42 d of age was only present in sera of 10 offspring broiler flocks of the nonvaccinated breeders. However, a lack of seroconversion to MG occurred in 10, 42-d-old offspring broiler flocks of the five ts-11-vaccinated breeder flocks. This lack was associated with a lower, better average feed-conversion ratio (2.05) (P < 0.05) and a lower average mortality percentage (5.3%) (P < 0.05) in comparison with those obtained in the offspring of the five unvaccinated, MG-infected breeder flocks. The results indicate that vaccination of broiler chicken breeders with a temperature-sensitive mutant of MG prevented infection by field MG in tracheas and infraorbital sinuses of these breeders and in the vitelline membranes of their embryos. In addition, the broiler offspring of the vaccinated breeders had a better production performance.

Animals↗

PubMed2000

Cardio-pulmonary function in preascitic (hypoxemic) or normal broilers inhaling ambient air or 100% oxygen.

We evaluated the influence of the percentage saturation of hemoglobin with oxygen (HbO2) on the pulmonary arterial pressure in normal and preascitic (hypoxemic) broilers breathing ambient air or 100% O2. In Experiment 1, unanesthetized preascitic broilers (right:total ventricular weight ratios [RV:TV] = 0.32+/-0.02) breathing ambient air had initial values of 67% for HbO2 and 32 mm Hg for pulmonary arterial pressure. The HbO2 increased to > or =96.6% during inhalation of 100% O2; however, pulmonary arterial pressure was not reduced. In Experiment 2, anesthetized normal (RV:TV = 0.23; HbO2 = 88%) and preascitic broilers (RV:TV = 0.28; HbO2 = 76%) were compared. The groups did not differ in body weight or respiratory rate, but preascitic broilers had lower values for mean arterial pressure, total peripheral resistance, and partial pressure of O2 in arterial blood and had higher values for pulmonary arterial pressure. Inhaling 100% O2 increased HbO2 to 99.9% in both groups; however, pulmonary arterial pressure remained higher in preascitic than in normal broilers, and the pulmonary vascular resistance was not reduced during 100% O2 inhalation. Cardiac output was higher in preascitic than in normal broilers before and after, but not during, 100% O2 inhalation. Mean arterial pressure and total peripheral resistance increased in the preascitic but not in the normal group during 100% O2 inhalation. Low coefficients of determination (R2) were obtained for linear regression comparisons of HbO2 vs. pulmonary arterial pressure in both experiments. Overall, acute reversal of the systemic hypoxemia in preascitic broilers had little direct impact on pulmonary hypertension, providing no evidence of hypoxemic or hypoxic pulmonary vasoconstriction. Instead, acute reversal of the systemic hypoxemia primarily increased the total peripheral resistance and normalized the mean arterial pressure and cardiac output. A sustained reduction in cardiac output theoretically should attenuate pulmonary hypertension, but this was not observed because of the overriding influence of sustained pulmonary vascular resistance.

Animals↗

PubMed2000

Effects of the trichothecene mycotoxin diacetoxyscirpenol on feed consumption, body weight, and oral lesions of broiler breeders.

Three experiments were conducted to determine the effects of 4,15-diacetoxyscirpenol (DAS) on BW, feed consumption, and oral lesions of broiler breeders. In Experiment 1, caged broiler breeder hens were fed 0, 5, 10, or 20 mg DAS/kg diet from 24 to 25 wk of age. There were dose-related decreases in BW and feed consumption indicating feed refusal, as well as dose-related increases in the extent of mouth lesions. The areas of the mouth most sensitive to DAS were associated with the salivary glands and the tip of the tongue. In Experiment 2, individually caged male and female broiler breeders were fed a basal diet containing 0, 5, 10, or 20 mg DAS/kg from 25 to 27 wk of age. There were dose-related decreases in BW and feed consumption for the female broiler breeders, whereas there was a decrease in feed consumption for the male broiler breeders at the 10 and 20 mg DAS/kg levels. In Experiment 3, male broiler breeders were fed 0 or 10 mg DAS/kg diet from 23 to 25 wk of age on a litter floor. For this experiment the daily intake of feed was restricted, and the feed consumption rate was measured. There was an increased amount of unconsumed feed at 23 wk of age due to the presence of DAS. In summary, the experiments provided evidence that DAS caused decreased BW and feed consumption as well as cytotoxic injury including oral lesions in broiler breeders.

Animals↗

PubMed2000

Male broiler breeder fowl display high levels of aggression toward females.

Commercial broiler breeder males are reported to display high levels of aggression, often injuring and sometimes killing females. Aggression toward females by mature male domestic fowl is rare and may be regarded as aberrant behavior. The objective of this study was to determine the effects of genetic strain and feed restriction on the sexual and aggressive behavior of male domestic fowl. A 3 x 2 factorial design was used to compare the behavior of three genetic strains (two broiler breeder strains and one commercial laying strain) on two feeding regimens (one restricted and one fed ad libitum) between 25 and 37 d of age. At 22 wk of age, pairs of same-strain males were penned with 20 females of a broiler breeder strain. Behavior was sampled from each pen for six 10-min periods during Weeks 25, 27, 29, 33, and 37. Broiler breeder males displayed significantly more male-to-male (P < 0.0197) and male-to-female aggression (P < 0.0005) than laying strain males. Broiler breeder males chased females (P < 0.0001), forced more copulations (P < 0.0003), and displayed little courtship behavior (P < 0.0001) compared with laying strain males. There were no behavioral differences between broiler breeder strains. It was expected that feed restriction would result in increased aggression. However, males fed ad libitum displayed the most male-to-male (P < 0.0035) and male-to-female (P < 0.0273) aggression. Sexual behavior was not affected by feeding regimen. In conclusion, broiler breeder males display aberrant sexual behavior and extremely high levels of aggression, which are associated with genetic differences, not feed restriction.

Aggression↗

PubMed2002

Dietary linseed oil produces lower abdominal fat deposition but higher de novo fatty acid synthesis in broiler chickens.

Previous experiments have shown lower abdominal and body fat deposition in broilers fed polyunsaturated fatty acids (PUFA) compared with those fed saturated fatty acids (SFA) or monounsaturated fatty acids (MUFA). These changes in fat deposition may be related to different rates of lipid synthesis or lipid oxidation. In Experiment 1, in vivo lipogenesis of broilers fed different dietary fatty acid profiles (tallow, sunflower oil, or linseed oil) was investigated. In Experiment 2, liver fatty acid deposition of broilers fed a basal diet (without additional fat) or diets with added tallow, olive oil, sunflower oil, or linseed oil was studied. Results from Experiment 1 showed higher rates of de novo fatty acid synthesis in broilers fed the diet with added linseed oil (P < 0.05), compared with those fed tallow or sunflower oil. In Experiment 2, values of liver-to-dietary-fatty-acid ratios of fatty acids from endogenous synthesis (SFA, n-7 and n-9 fatty acids) were higher in broilers fed linseed oil and the basal diet. Results obtained in both experiments suggest that lower abdominal and body fat deposition of broilers fed PUFA compared with those fed SFA or monounsaturated fatty acids is mainly due to differences in lipid oxidation rates and that the higher in vivo lipogenesis found in broilers fed linseed oil would be another mechanism to dissipate energy, contributing to the lower fat deposition in these birds.

Abdomen↗