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Changes in soil nitrogen and phosphorus under different broiler production systems.

In a field study, soils of four conventional free-range and organic broiler runs were analyzed for N and P concentrations in the years 2000 and 2001. Zones of different use intensity by broilers were identified on the free runs and mean zonal nutrient contents were compared with each other. Intensity of use by birds and spatial distribution of soil nutrient concentrations were found to be related to each other. Fecal N input by broilers resulted in accumulation of soil mineral nitrogen (N(min)) contents down to a 90-cm sampling depth. In highly frequented "hot spots," plant requirement as defined by the German "N-Basis-Sollwert" (110 kg/ha N(min)) for grassland was exceeded in all four cases. This implies an increased environmental risk of ammonia volatilization and nitrate leaching. Fecal P input by broilers resulted in accumulation of plant-available and thus mobile soil P (phosphorus extracted with calcium-acetate-lactate [P(CAL)] and phosphorus extracted with water [P(w)]) in the most intensely used zones. In these areas, soil P contents exceeded 90 mg/kg P(CAL) (upper limit of soil test P defined in Germany for optimum plant yield) by as much as 217 mg/kg, which indicates an enhanced risk of P loss from the soil via runoff or leaching. The conclusion might be drawn that, with regard to nutrient loss from free-run soils, intensive indoor production in a closed system may be more environmentally neutral than conventional free-range or organic production. However, to put this into perspective, the scope of the environmental risk connected with spatially limited point accumulation of nutrients should be considered. Furthermore, an environmental evaluation must also account for the fate and environmental effects of the broiler litter produced inside the broiler house.

Animal Husbandry↗

PubMed1999

Ubiquitin gene expression and ubiquitin conjugation in chicken muscle do not reflect differences in growth rate between broiler and layer birds.

Previous work has shown that chicken strains selected for growth (broilers) degrade muscle proteins less rapidly than those selected for egg laying. They also have decreased calpain and increased calpastatin content in breast muscle. This study aimed to test the hypothesis that these differences correlate with changes in the ATP- and ubiquitin-dependent proteolytic system. Chickens of a broiler strain (Ross 1) and a layer strain (ISABrown) were reared to the age of 4 wk under identical conditions with ad libitum access to feed and water. Mean fractional growth rates were 10.4%/d for broilers and 7.4%/d for layers. Feed intake measured in the last week of the trial was slightly greater in layer birds (.11 and .12 g x g body weight(-1) x d(-1) for broilers and layers respectively; P < .006). Polyubiquitin (UbI) messenger RNA was abundant in the muscles of these well-fed birds, but it showed little difference between strains. Muscle did not significantly express the UbII polyubiquitin gene. The ATP-dependent system conjugating ubiquitin to endogenous proteins had greatest activity in the gastrocnemius muscle of broiler birds but was not significantly different between breeds. Proteins cross-reactive with antisera to recombinant human proteasome regulatory subunits MSS1 (multicopy suppressor of SUG 1; S7) and TBP1 (tat binding protein 1; S6') were present in muscle homogenates from both strains of bird. The chick equivalent of TBP1 was more abundant in breast muscle of broiler birds than in leg muscle, or in either muscle of layers. Antiserum to recombinant yeast subunit mts2 (mitosis temperature sensitive gene 2; S4) did not react with any protein of the expected size but detected a 30-kDa peptide that was not associated with the 26S proteasome; this was found only in muscle from the layer strain. Hence, during normal growth of chickens, rates of protein degradation are not controlled by the expression of ubiquitin mRNA or the conjugation of ubiquitin. However, the composition of the 26S proteasome may be a regulatory factor.

ATPases Associated with Diverse Cellular Activitie↗

PubMed1999

Enhancement of cellular and humoral immunity in young broilers by the dietary supplementation of beta-hydroxy-beta-methylbutyrate.

As a dietary supplement, beta-Hydroxy-beta-Methylbutyrate (HMB), a catabolite of leucine, has been shown to reduce broiler mortality. In a series of experiments, male broilers (Experiments 1 and 2, n = 576) were grown for 21 days on diets that contained HMB at 0, 0.01. 0.05, and 0.10% of diet. In Experiment 3 (n = 240), chicks were fed diets containing 0, 0.05, 0.075, and 0.10% HMB. HMB dietary supplementation did not significantly affect broiler weight gain in any experiment. However, a trend toward increased mean broiler weight gain per bird was observed in Experiments 1 and 3 when HMB was consumed at 0.10% of the diet. Mean feed to gain ratio was not affected by the inclusion of HMB in broiler diets. In Experiment 3, HMB supplemented diets did not affect bursa of Fabricius, thymus, and spleen weights at 21 days of age. Cutaneous basophilic hypersensitivity response against pokeweek mitogen was higher (P < or = 0.05) at 48 and 72 hours post-injection in chicks on 0.05% dietary HMB (Experiment 1). In Experiment 2, this increase occurred 24 hours post-injection in chicks fed HMB at 0.01% of the diet. On the contrary, the T-cell mediated response against PHA-P mitogen was comparable between all dietary treatments in multiple experiments. Macrophage function profiles were determined at 21 days of age. All chicks in experiments 1 and 2 on HMB supplemented diets showed an increase in the recruitment of Sephadex-G50-elicited abdominal exudate cells (AEC). A 2-fold increase in AEC numbers occurred at the 0.10% HMB level (Experiment 1, P < or = 0.05). Although HMB supplementation did not significantly affect the phagocytic potential of the abdominal macrophages, nitrite levels in the macrophage culture supernatants were higher in 0.01% and 0.05% treatment groups as compared to the controls (Experiment 2, P < or = 0.04; Experiment 3, P < or = 0.05). HMB supplementation did not alter the bird's ability to clear Escherichiacoli or Salmonella arizona from the bloodstream. Beginning 7 days post-hatch, chicks were injected i.v. with a 7% sheep red blood cells suspension. Serum samples were collected to determine the primary and secondary antibody response. Chicks receiving the 0.1% HMB diet in Experiments 1 and 2 exhibited increased IgG and total anti-sheep red blood cell (SRBC) antibody levels during the primary response. During the secondary response, birds consuming the 0.10% HMB diet had elevated IgM levels as well as increased total anti-SRBC levels over the controls in Experiments 1 and 3. These studies show that HMB supplementation improves several immunological functions in young broilers, and such improvement may result in decreased mortality.

Adjuvants, Immunologic↗

PubMed2001

Deep-stacked broiler litter as a protein supplement for dairy replacement heifers.

Fifty Holstein dairy heifers, [two replications of 25 heifers; average body weight (BW) 227 kg], were assigned to one of the following treatments for 105 d. Treatments 1 through 4 are given as the percentage of supplemental crude protein (CP) from soybean meal and deep-stacked broiler litter, respectively: 1) 100 and 0%; 2) 67 and 33%; 3) 33 and 67%; 4) 0 and 100%; and 5) 67% of supplementary CP from deep-stacked broiler litter and 33% from a source of rumen undegradable protein (RUP). All rations were formulated to contain 15% CP and 68% TDN on a dry matter basis. Dry matter intake was not significantly different among treatments at 10.1, 10.2, 10.4, 9.4, and 9.1 kg/d for treatments 1 through 5, respectively. Average daily BW gains (1.35, 1.37, 1.28, 1.17, and 1.24 kg/d for treatments 1 through 5, respectively) decreased linearly as the level of litter feeding increased and was not influenced by increasing RUP in treatment 5. Feed efficiency was not affected by the level of deep-stacked broiler litter feeding. Ruminal ammonia and plasma urea nitrogen concentrations decreased linearly as the level of litter feeding increased. Feeding additional RUP decreased ruminal ammonia concentration in treatment 5 to a level similar to treatment 4. This suggests that the protein in deep-stacked broiler litter may be more undegradable than that in soybean meal and that RUP in broiler litter may be higher than previously thought. Results from this study indicate that deep-stacked broiler litter has potential as a low-cost CP source for growing dairy heifers.

Ammonia↗

PubMed1977

The effect of sex, dietary energy, meat protein, ascorbic acid and iron on broiler skin collagen.

Two studies were conducted to determine if variation of sex, dietary energy, meat protein, ascorbic acid or iron had any effect on collagen metabolism in broilers. In the first experiment day-old broiler type chicks were fed diets which contained 3190 or 3410 kcal. M.E./kg. of diet, 0 or 15% meat and bone meal and 0 or 1 g./kg. ascorbic acid. In the second experiment the day-old broiler chicks were fed diets which had 3190 or 3410 kcal. M.E./kg. of diet and 60 or 260 p.p.m. of iron. At 56 days of age the broilers were weighed, a representative number of birds killed from each group and skin samples collected. The skin samples were analyzed for the degree of collagen cross-linking and the total and insoluble collagen contents. An alteration of energy, meat protein, ascorbic acid or iron in the diet had no effect on collagen formation in the skin of broilers reared in cool environmental temperatures. Female broilers had a significantly higher percentage of insoluble collagen in the skin tissue but the level of total collagen and insoluble collagen was higher in the male birds.

Animals↗

PubMed1981

A comparison of bone strengths from broilers reared under various conditions in coops and floor pens.

A series of four trials was conducted to compare the influence of several design variables on the strength of bones from coop and floor-reared broilers. So that the activity of coop-reared broilers would increase, a fan system intermittently forced air up through the bottom of the coops. Because the broilers became accustomed to the intermittent force of air, the induced extra activity decreased after the first 7 days of fan use. No differences in bone strength were observed in broilers reared in the control and fan-treated coops. Broilers reared in floor pens with a screen covering placed at a height equal to the height of the coops (29 cm) had significantly (P less than .01) weaker wing bones than floor-reared controls. When the height of the screen was increased to 46 cm, no significant difference was observed in the strength of wing bones of broilers in the screened and control pens.

Animals↗

PubMed1981

Influence of age and sex of growing broiler chicks and body weight of roosters on their endogenous and metabolic energy losses.

Two experiments were conducted to study the influence of age, sex, body weight, and strain of the bioassay bird on its 24-hr combined endogenous urinary and metabolic fecal energy (Yec) losses, expressed as kJ/100 g body weight per 24 hr. In the first experiment, one-day-old broiler chicks of mixed sexes were used and their Yec losses determined at 18, 32, 47, 62, 77, 92, and 107 days of age. In the second experiment, the Yec losses of four White Leghorn roosters were determined at 122 days of age only. Birds were fed a commercial broiler-starter diet through-out the experimental period. It was concluded that the sex of the broiler chick between 18- and 107-days of age does not affect the Yec losses, i.e., the energy the unfed bird loses daily per unit body weight in its voided excreta. However, the average Yec losses expressed (either per unit body weight or per unit body size, Wkg.75 were influenced by age. The Yec losses showed a progressive fall as broiler chicks progressed in age between 18 and 77 days of age and later were stabilized at a minimum between 77 and 107 days of age. As the observed decrease in the Yec losses with increases in age followed a similar trend to that reported in the literature for the basal metabolic rate (BMR) energy needs of the chick, it was tentatively concluded that the Yec losses of broiler chicks vary with age according to the BMR energy needs per unit body weight of the animal. The average Yec losses of White Leghorn roosters at 122 days of age was significantly higher than that of 107-day-old broiler pullets even though the average weight of the rooster was only 53% that of the pullets. It was tentatively concluded that variations existing in the Yec losses of adult birds of same or different strains and sex are mainly attributed to differences in their body composition and BMR energy needs. However, further research is needed in order to verify this conclusion.

Age Factors↗

PubMed1981

Tibial dyschondroplasia in broilers: comparison to dietary additives and strains.

The effects of broiler strain and various additives to practical corn-soy diets on the incidence of tibial dyschondroplasia (TD) were studied using broiler chicks maintained in battery brooders. At the termination of each experiment, birds were killed and examined for TD by cutting longitudinally along the tibia. No significant difference in the incidence of TD was found among the nine broiler strains compared. While the incidence of twisted legs was higher than TD among the nine strains there was no apparent correlation between the two leg disorders. Studies conducted using the following additives did not significantly increase the incidence of TD in broilers when compared to controls: monensin, sodium chloride, copper sulfate, magnesium sulfate, potassium sulfate, roxarsone, gentian violet, erythromycin, vitamin K, or vitamin D3. However, dietary ammonium chloride (1.5 or 30%) did increase the incidence of TD, whereas adding various fermentation products at levels of 10 and 20% either in the absence or presence of ammonium chloride failed to reduce the incidence of the disease. The incidences of TD among broiler chicks fed high dietary fluoride were nonsignificant; no evidence of the disease was found in Leghorn chicks fed the same diets. Chicks maintained in battery brooders in these studies, generally had a lower incidence of TD than that reported for commercial flocks in the field. Furthermore, manipulation of feed additives or ingredients in practical rations for broiler chickens did not increase the incidence of the disease.

Animal Feed↗

PubMed1982

The effect of the scaleless gene, sc, on growth performance and carcass composition of broilers.

Two experiments were conducted in which featherless broilers (scaleless, sc/sc) were compared with feathered broilers for growth and body composition characteristics at environmental temperatures of 22, 34, and 38 C. The sc gene reduces growth and efficiency at 22 C but at 38 C the sc/sc broilers gain more, eat more, and are more efficient than feathered broilers. They achieve greater live, New York dressed, and eviscerated weights and consistently have greater eviscerated yields. The sc/sc broilers have more protein and mineral content and less fat than the feathered broilers.

Animals↗

PubMed1983

Factors affecting broiler processing parameters and plasma corticosterone.

Two experiments were conducted to determine the influence of broiler strain, sex, and age on resting plasma corticosterone levels and the latter's relationship to various broiler production and processing parameters. In Experiment 1, strain and sex differences in 58-day farm weight (FWT), dressed carcass weight (DC), yield (Y), abdominal fat (AF), abdominal fat expressed as a percentage of DC (PAF), and plasma corticosterone (C) measures were assessed in five commercial broiler strains fed a lower [3086 kcal metabolizable energy (ME)/kg] versus higher (3306 kcal ME/kg) energy ration. The higher energy diet was formulated and used to produce excess abdominal fat. In Experiment 2, the effect of broiler age (4, 6, and 8 weeks) on resting plasma C was determined. Results of Experiment 1 indicated that although strain significantly influenced AF, and although feeding the higher energy diet significantly elevated FWT, DC, Y, AF, and PAF, strain and dietary energy effects on plasma C were nil. However, a significant strain X dietary energy interaction on plasma C levels was observed. Likewise, although female broilers had greater PAF measures than male birds, sex did not influence resting plasma C values. Plasma C was not correlated to AF measures. Experiment 2 results showed plasma C at 6 (3.3 ng/ml) and 8 weeks (2.9 ng/ml) was significantly depressed from the 4-week (4.9 ng/ml) sampling. Thus, future studies involving adrenal functioning in broilers should take into consideration the influence bird age might have on interpretation of results.

Adipose Tissue↗

PubMed1983

The effect of dietary energy level and broiler body weight on abdominal fat.

Utilizing a moderate rearing temperature regimen, two trials were conducted to determine the effect of dietary energy level on the amount of abdominal fat deposited when broilers are grown to equal body weight by varying growth time. The most abdominal fat (2.29% average of live weight for male and females) was produced by broilers offered a diet calculated to contain 3325 ME kcal/kg. The least amount of abdominal fat (1.92% average of live weight for male and females) was produced by broilers offered diets calculated to contain 3100 and 3175 metabolizable energy (ME) kcal/kg. In one additional day (48 vs. 47 days) the growth of the broilers offered diets calculated to contain 3100 and 3175 ME kcal/kg equalled that of broilers offered diets calculated to contain 3250 and 3325 ME kcal/kg. Feed conversion (g feed/g live weight) significantly decreased as dietary energy level increased. Three additional trials were conducted to determine when abdominal fat is deposited in relation to age and weight. It was found that male broilers offered diets calculated to contain 3325 ME kcal/kg had as much abdominal fat when expressed as a percent of body weight at 40 days of age as they did at 53 days of age.

Abdomen↗

PubMed1984

Response of broiler chickens to dietary energy and lysine levels in a warm environment.

Two trials were conducted to determine the response of 23- to 47-day-old broiler chickens to dietary lysine and energy levels when reared in a 26.7 C environment. Broiler finishing diets, which contained 3100, 3175, 3250, or 3325 kcal ME/kg of feed were fed in combination with either .308 or .322% lysine/Mcal (kg) with a constant 18.7% dietary protein. Male and female body weights were not statistically different (P less than .05) among dietary energy levels when both sexes were fed .308% lysine/Mcal (kg). When the male chicks were fed .322% lysine/Mcal (kg), body weights increased with increasing dietary energy level. Feed utilization also increased with increasing dietary energy level when broilers were fed either .308 or .322% lysine/Mcal (kg). These data suggest that the body weight response to dietary energy level when broilers were reared in a warm environment will occur only when adequate amino acid levels are employed. The dietary energy requirement is at least 3250 kcal ME/kg of feed when 23- to 47-day-old broilers are fed .322% lysine/Mcal (kg) and reared in a hot environment but appeared to be lower when broilers were fed .308% lysine/kg of feed.

Animals↗

PubMed1985

The effect of intermittent lighting on growth, feed:gain ratio, and abdominal fat content of broiler chickens of various genotypes and sex.

Intermittent lighting (IL) regimens were tested for rearing broiler chickens from 2 to 7 weeks of age. In Experiments 1 and 2, the effects of 6 cycles of light (L) and darkness (D) of 1L:3D vs. 12 cycles of .25L:1.75 D were compared on the performance of 2400 broiler chickens. Eight genotypes of 5170 mixed-sex broilers were used to compare effects of 6 cycles of 1L:3D vs. 1 cycle per day of 23.5L:.5D on broiler performance (Experiment 3). The sexes responded differently to two IL regimens in Experiment 1. Males had higher body weight, feed intake, and abdominal fat content with 1L:3D; in females, there was no difference in body weight or feed intake, but abdominal fat content was lower with 1L:3D regimen. In Experiment 2, no significant effect of lighting regimen on broiler performance was observed. In Experiment 3, most genotypes had lower feed intake and abdominal fat content for 1L:3D than for 23.5L:.5D, but response of weight gain was variable; one genotype had higher feed intake and another genotype had higher fat content with 1L:3D. It was concluded that sex and genotype should be considered in planning the use of IL techniques for broiler chickens.

Abdomen↗

PubMed1985

Effects of aflatoxin on young turkeys and broiler chickens.

The effect of crude aflatoxin (AF) on the growth, performance, and immune response of turkeys and broilers was studied. Crude AF, produced from a natural outbreak of Aspergillus flavus on corn, was ground and mixed in rations to contain either 0, 100, 200, 400, or 800 ppb of aflatoxin B1 (AFB1). Turkeys (Experiment 1) and broilers (Experiment 2) were used in identical experimental designs. In each, 200, 14-day-old birds were divided equally by sex into five groups of 40 and were fed one of five AF diets for 35 days. In Experiment 1, crude AF greater than or equal to 400 ppb was highly toxic to turkeys. These levels produced signs and lesions of aflatoxicosis as well as a significant decrease in weight gain and feed conversion during 5 weeks. In addition, microscopic lesions, indicative of aflatoxicosis, were evident as low as 100 ppb, and significant decreases in cell-mediated immunity were noted in the 200 ppb group birds. Experiment 2 indicated that chickens were less susceptible to crude AF than turkeys. Neither morbidity nor mortality occurred in broilers. Gross lesions consistent with AF toxicity were evident in birds given 800 ppb and microscopic lesions were observed in birds given 100 ppb. Feed conversion was significantly increased in the 800 ppb broilers only. Cell-mediated immunity, measured by a delayed hypersensitive skin test, was significantly decreased in broilers receiving AF at 200 ppb or greater. Neither humoral immunity nor the development of the acquired immunity to Newcastle disease or fowl cholera vaccination were decreased in turkeys or broilers given AF.

Aflatoxins↗

PubMed1986

Adipose tissue cellularity and growth characteristics of unselected and selected broilers: implications for the development of body fat.

Chicks from large and small eggs were used to increase body weight range within samples of unselected Athens-Canadian (AC) and commercial Cobb (C) broilers. At 54 days of age, representatives of each sex and broiler stock obtained from the large and small eggs were killed. Indices of whole body, muscle, fat, and bone growth were taken. Samples of abdominal fat were fixed with osmium tetroxide for electronic quantification of adipocyte number and size distribution. Broiler stock, egg size, and sex affected all indices of muscle and bone growth on an absolute basis, but only broiler stock significantly affected abdominal fat pad development. Muscle and fat weight, expressed as a proportion of body weight, were larger in C broilers. Abdominal adipocyte number was greater in C than AC (126.0 +/- 10.0 vs. 90.9 +/- 7.7 million, P less than .01), but the greater adiposity of C was associated with an increase in adipocyte size. If the mean adipocyte volume of C (120.4 +/- 8.5 pl) was reduced to the mean adipocyte volume of AC (53.8 +/- 6.5 pl), proportional weight of the abdominal pad of C would have been smaller than proportional pad weight of AC. The problem of excessive abdominal fat deposition in the selected broiler stock appears related to factors that affect control of adipocyte size and body composition.

Adipose Tissue↗

PubMed1988

Effect of environmental temperature and feeding regimen on quantity of digestive tract contents of broilers.

Carcass contamination from contents of the digestive tract during processing is a recurring problem for the broiler industry. Environment and feeding regimen are often implicated as causative factors. The effects of environmental temperature and meal feeding on passage of feed through the digestive tract of broilers were examined. Broilers were reared in environmental chambers in five experiments. In the first experiment, environmental temperatures were constant temperatures of 16 and 27 C and cycles of 16-24-16 and 24-35-24 C and rate of passage of feed through the digestive tract (ROP) was determined with ferric oxide. Temperature did not consistently affect ROP. In the other four experiments, various environmental temperatures were investigated and broilers were fed continuously or for 12 or 16 h/day. Contents of the crop, proventriculus plus gizzard, and small intestine were weighed 2, 4, 6, and 8 h after feeding withdrawal. Environmental temperature did not directly affect the movement of digesta but the feeding regimen affected the quantity of digesta in some segments of the tract. Environmental temperature may have indirectly affected the quantity of feed in the crop by affecting the quantity of feed consumed. Limiting the feeding period resulted in retention of digesta in the crop of some broilers for an extended period. This increased the variability in quantity of crop contents. A feeding regimen X temperature interaction resulted in increased small intestine weight for meal-fed broilers at 16 C.

Animals↗

PubMed1989

Ochratoxin A and dietary protein. 1. Effects on body weight, feed conversion, relative organ weight, and mortality in three-week-old broilers.

An experiment with a completely randomized 3 x 4 factorial design was used to study the effects of ochratoxin A (0, 2, and 4 mg/kg) and protein (14, 18, 22, and 26%) in three-wk-old broilers. The diets were based on ground yellow corn and dehulled soybean meal. Four hundred and eighty Hubbard x Hubbard broilers were randomly placed in battery brooders, with 10 birds per pen. Each treatment was replicated four times. Body weight increased with rising levels of protein, and decreased with rising levels of ochratoxin A (OA). The efficiency of feed utilization was improved in broilers fed 22 and 26% protein, compared with broilers fed 14 and 18% protein. The efficiency of feed utilization was lower for the birds fed 4 mg/kg of OA, compared with broilers fed 0 and 2 mg/kg of OA, respectively. Using OA increased the relative weight of the liver, kidney, spleen, pancreas, proventriculus, gizzard, and heart and also significantly decreased the relative weight of the bursa of fabricius. A significant interaction between OA and protein was seen in terms of the relative weight of the liver, pancreas, and gizzard, indicating that the rising protein levels spared the OA effect on those organs. Mortality was highest among the broilers fed 4 mg/kg of OA. Protein regression coefficients (beta's) were positive with respect to 21-day body weight and were negative for the feed:gain ratio and mortality, suggesting that protein provided beneficial effects.

Animal Feed↗

PubMed1990

The effect of light and environmental temperature on broiler digestive tract contents after feed withdrawal.

Contamination from the digestive tract is a persistent problem in broiler processing. Two experiments were conducted to determine the effects of lighting and environmental temperature on quantity of crop, gizzard, and small intestine contents during feed withdrawal. Broilers were on litter with a feeding regimen of 1.5 h on feed and 4.5 h off feed for 1 or 2 days. The withdrawal period began at the end of a 1.5-h feeding period. In the first experiment, broilers were cooped or left on the floor with and without lights. Crop contents of lighted broilers at 21 C were reduced 2 h after feed withdrawal for broilers on litter and in coops. In another experiment, broilers on litter were maintained at 18 and 27 C in light or in darkness. Lighting reduced crop contents 4 h after feed withdrawal but increased the contents of the small intestine 2 h after feed withdrawal at both temperatures. These results indicate that crop clearance is improved by lighting both before and after cooping.

Animals↗