Hubbard Broiler Research Articles

Bone Strength Statistical Distribution Functions for Broilers

Shear and three-point bending tests were conducted on the femur and tibia bones from Hubbard broilers to establish the type of statistical distribution function that best fits bone strength data. In the past it was assumed that these types of data followed a normal distribution.The results of this investigation indicate that a log-normal function best describes the mechanical properties of the tibia and a normal function describes the properties of the femur. Overall the results of the distribution analysis indicate that the mechanical properties of bone tend to follow a log-normal distribution.

The Effect of Feeding Four Fish Hydrolyzate Meals on Broiler Performance and Carcass Sensory Characteristics

Hubbard broiler chicks were fed to 7 weeks of age diets containing hake (Pacific whiting), Dover sole, Brown rock, and Atlantic cod hydrolyzate meal to provide 4.3% crude protein in diets and herring meal to provide 4.9% crude protein in the diet (dry matter basis). No significant differences were observed among the treatments in live body weight and feed conversion; however, mean dressed broiler weight (P<.05) was influenced by the type of fish meal. The diets affected drip cooking loss (P<.05) and the fishy and off-flavor sensory characteristics of the cooked broiler carcasses. There were no differences (P>.05) due to diet in total cooking losses, cooking time, total moisture, and juiciness.

The Effect of Polyether, Ionophorous Anticoccidial Drugs on Feather Growth in Genetically Slow-Feathering Broilers

The rate of feather growth was measured in Hubbard × Hubbard broilers given monensin, salinomycin, or lasalocid for 8 weeks in floor pens. Chicks were given a nutritionally adequate diet.Feathers on male chicks were shorter at 10 days of age but grew faster than those on female chicks. Male chicks had longer feathers than female chicks after 31 days of age. Back feather scores were similar in male and female chicks at 52 days of age.Dietary ionophores had no effect on the rate of feather growth or the back feather coverage under the condition of this study.

The Effect of Feeding Di-(2-Ethylhexyl) Phthalate and Related Compounds on Lipids in the Laying Hen

Di-(2-ethylhexyl) phthalate (DEHP) and three structurally related side-chain analogs were fed to laying hens to determine relationships of structure to effects on lipid metabolism. Hubbard broiler breeder hens were fed either a standard laying mash control diet or the control diet containing DEHP, 2-ethylhexanol (2-EH), 2-ethylhexanal (2-EHALD), or 2-ethylhexanoic acid (2-EHA). Experimental treatments lowered feed consumption, body weight, and egg production. The DEHP and side-chain analog diets lowered plasma total lipids. DEHP, 2% 2-EH, and 1% 2-EHA diets lowered plasma free cholesterol. Liver weights were not significantly changed, but liver fat was reduced. Lipid classes were measured by quantitative thin layer chromatography densitometry. The decreases observed in plasma lipids occurred primarily in the triglyceride fraction. Liver lipid decreases occurred mainly in triglyceride and free fatty acid classes.Hen egg yolk percent fat, lipid classes, and free and total cholesterol were unaffected by any DEHP or side-chain analog diets. Plasma and liver hypolipidemic effects were observed with all of the oxidation state structural analogs of DEHP's side chain, but 2% 2-EH was the most effective treatment. These results suggest that the active portion of DEHP may be the metabolite, 2-EH, formed in vivo by hydrolysis of DEHP's ester bond.

Experimental Induction of Chronic Aflatoxicosis in Chickens by Purified Aflatoxin B1 and Its Reversal by Activated Charcoal, Phenobarbital, and Reduced Glutathione

Aflatoxin B1 (AFB1) caused dose-dependent reductions in weight gain and feed consumption when day-old Hubbard × Hubbard broiler type chicks were maintained on a diet contaminated with either 0, 2.5, 5, or 10 ppm purified AFB1 for 8 weeks. Although changes in these parameters were detected at the 2.5 and 5 ppm, the most profound changes were evident at 10 ppm contamination. The concentration of cytochrome P-450 in hepatic microsomes, measured at the end of 8 weeks, also showed dose-dependent decreases. Cytochrome P-450 content in chickens receiving 2.5, 5, and 10 ppm AFB1 was 16, 28, and 65%, respectively, less than the control. Microsomal benzphetamine N-demethylase activity was not inhibited by 2.5 or 5 ppm, but ingestion of 10 ppm AFB1 reduced its activity by more than 40%. Serum glutamic oxalacetic transaminase (SGOT) levels of chickens receiving 10 ppm AFB1 increased by more than 100%, indicating substantial liver damage. However, birds simultaneously receiving 10 ppm AFB1 and activated charcoal (.1% in the feed) or either reduced glutathione (.05%) or phenobarbital (.05%, given intermittently) in their drinking water showed a trend of improvement in feed consumption (<10% reversal) and weight gain (<28% reversal) over the birds receiving 10 ppm AFB1 alone. The results also indicate that the simultaneous presence of these agents with AFB1 considerably prevented the inhibitory effect of AFB1 on the microsomal cytochrome P-450 and benzphetamine N-demethylase activity. Furthermore, these agents were able to provide moderate protection against AFB1-induced liver injury manifested by elevation of SGOT activity.

Weight Gain and Feed Efficiency of Chicks Fed Sucrose Fatty Acid Esters

Day-old Hubbard × Hubbard broilers (mixed sexes) were fed for 2 weeks with a basal diet containing 5% experimental carbohydrate. The experimental carbohydrates were one of the following: sucrose fatty acid esters (SFE)-high monoesters (SFE 1670), SFE-low monoesters (SFE 370), sucrose, glucose, or cellulose. Feed efficiency, weight gain, and growth performance were compared among treatments.Chicks fed 5% SFE 1670 showed significantly less (P<.01) weight gain and feed efficiency than chicks fed other experimental carbohydrates. There were no significant differences (P<.01) in weight gain and feed efficiency among groups of chicks fed SFE 370, sucrose, glucose, or cellulose. Most of the chicks fed SFE 1670 were small in size, had poor feathering, and excreted reddish-brown droppings. The appearance and droppings obtained from chicks fed SFE 370 were similar to the appearance and droppings from chicks fed sucrose, glucose, and cellulose. The SFE that contained a large proportion of monoesters (SFE 1670) resulted in poor growth of chicks, whereas SFE containing a small proportion of monoesters (SFE 370) resulted in growth performance similar to chicks on control diets.

Toxic Effects of Aflatoxin B 1 in Chickens Given Feed Contaminated with Aspergillus flavus and Reduction of the Toxicity by Activated Charcoal and Some Chemical Agents

Aspergillus flavus NRRL 3357 was grown on enriched long-grain rice for 7-10 days to produce aflatoxin B1 (AFB1). The quantity of AFB1 in moldy rice was determined by thin-layer chromatography using ultraviolet light. When the dried moldy rice powder was fed to day-old Hubbard X Hubbard broiler chicks in unmedicated feed (AFB1 level 10 ppm) for 8 weeks, there was a profound reduction in weight gain and feed consumption. Chickens fed AFB1 developed severe liver damage, as determined by the concentration of hepatic microsomal cytochrome P-450 and by the activities of microsomal benzphetamine N-demethylase and serum glutamic oxalacetic transaminase. However, activated charcoal, reduced glutathione, cysteine, selenium (as sodium selenite), beta-carotene, and fisetin administered orally considerably reduced the toxicity of AFB1 in the experimental chickens.

Utilization of Supplemental Methionine Sources by Primary Cultures of Chick Hepatocytes

Utilization of 2-hydroxy-4-(methylthio) butanoic acid (HMB) as a substrate for protein synthesis was studied by using primary cultures of chick liver cells. Cultures were prepared by enzymatic dissociation of livers from week old Hubbard broiler chicks and were maintained for 4 days under nonproliferative conditions. Hepatocyte differentiation was verified by using dexamethasone induction of tyrosine aminotransferase activity. Conversion of [14C]HMB to L-methionine was shown by chromatographic analysis of hepatocyte protein hydrolysate and incorporation into protein was proven by cycloheximide inhibition of synthesis. When incorporation of HMB was compared to that of DL-methionine (DLM) equimolar quantities of the two sources were found in liver cell protein. These results support, at a cellular level, the conclusion that HMB and DLM are biochemically equivalent sources of methionine for protein synthesis.

Effects of Dietary Restriction on Reproductive Performance of Broiler Breeder Males

Hubbard × Hubbard broiler breeder males were raised to 30 weeks of age following the Management Guide for the Hubbard White Mountain Male (Hubbard Farms, 1979). From 30 to 54 weeks of age, males were provided with five different levels of feed intake. The level recommended by the guide (154 g/bird/day) was designated to be the control level (100%). Other levels were 115, 85, 70, and 55% of the control. The effects of feed intake on body weight, fertility, hatchability, semen volume, and testes size were determined. No significant effects of feed intake were noted on fertility or hatchability. Body weights were significantly decreased as feed intake was decreased. Semen volume was greatest for males fed 85% of the control, while birds fed the control had the largest testes as a percentage of body weight. Males receiving the control feed gained only 28 g over 24 weeks, indicating that approximately 458 kcal/bird/day is adequate for maintaining body weight.

Factors Affecting Broiler Breeder Performance: 3. Relationship of Body Weight During Fasting to Postmolt Performance

Two experiments were conducted to assess the relationship of body weight during a 12-day fast to postmolt performance of broiler breeder hens. The hens were individually caged Hubbard broiler breeders and were force molted by reducing the photoperiod, withdrawing feed for 12 days, and withdrawing water for 2 days. Body weight change during the fast was expressed as either body weight loss (LOSS) during the 12-day fast or as the body weight (BDWT) on Day 12.Egg production, egg shell quality (specific gravity), and egg weight were assessed for seven or eight 28-day periods. Fertility and hatch of fertile eggs were also determined.Improved postmolt egg production and reduced egg weight were more closely associated with BDWT than LOSS. No other consistent relationship was found. These data demonstrated that a body weight of approximately 2.4 to 3.0 kg must be reached during a fast to maximize postmolt egg production under these experimental conditions.

Factors Affecting Broiler Breeder Performance: 2. Relationship of Daily Feed Intake to Performance of Force Molted Broiler Breeder Hens ,

Two trials were conducted to assess the effect of several daily feed intake levels on postmolt performance of individually caged Hubbard broiler breeder hens. The levels of maximum feed intake ranged from 127.2 to 172.5 g/hen/day. The layer ration was a corn-soy diet which contained 16% protein and 2805 kcal ME/kg of diet.Egg production, egg specific gravity, egg weight, and feed conversion were assessed on the basis of seven or eight, 28-day periods. Body weight, fertility, hatch of fertile eggs, and chick weights were assessed several times during the two trials.Hens exhibited higher egg specific gravities, lower egg weights, improved feed conversions, and lower body weights as daily feed intake decreased from 172.5 to 145.2 g/hen/day. Fertility and hatchability were affected similarly by feed restriction. Feed intake levels below 145.2 g/hen/day failed to elicit further improvement in the above parameters but did decrease egg production.

A Consumer Study of the Eating Quality of Broiler Chickens Fed Rations Containing Low Glucosinolate Rapeseed Meal and Rapeseed Screenings Meal

The eating quality of 8-week-old White Mountain × Hubbard broiler chickens fed four (Commercial-type) rations was evaluated by 110 consumer panelists. The rations were a soybean meal control ration (SBM), a 10% Tower rapeseed meal ration (RSM), a soybean meal ration with 10% rapeseed screenings meal (SBM + 10 RSSM), and a Tower rapeseed meal ration with 10% rapeseed screenings meal (RSM + 10 RSSM). Panelists received four coded frozen half chickens (one representing each ration treatment) and were instructed how to cook each defrosted chicken half. Consumer panelists scored the odor, flavor, and overall acceptability of the chickens and then ranked the chickens in order of preference. There were no significant differences in the odor, flavor, and overall acceptability of the cooked chickens attributable to ration. Mean scores given to each of the rations for preference rating of the cooked chickens show they were similar in eating quality, suggesting that the eating quality of chickens was not affected by the inclusion of 10% Tower rapeseed meal in the ration. Inclusion of 10% rapeseed screenings meal in either the SBM or RSM ration also had no effect on the eating quality of the broilers.

Influence of Low Glucosinolate Rapeseed Meal and Rapeseed Screenings Meal on the Eating Quality of Broiler Chickens

White Mountain × Hubbard broiler chickens were fed one of five rations: a soybean meal control ration (SBM), a 10% Tower rapeseed meal ration (RSM), a Tower RSM ration with 2.5% rapeseed screenings meal (RSM + 2.5 RSSM), a Tower RSM ration with 5% rapeseed screenings meal (RSM + 5 RSSM), or a Tower RSM ration with 10% rapeseed screenings meal (RSM + 10 RSSM). At 8 weeks of age, the chickens were killed, eviscerated, and frozen for later evaluation. Cooked light and dark meat and broth samples were evaluated by a trained panel. Some objective measurements were made. Inclusion of 10% RSM in the ration did not affect the eating quality of the cooked chicken meat and broth. Chickens from rations containing RSM and RSM with varying amounts of RSSM were generally similar. Judges rated the “other” score for the odor of dark meat from chickens fed the RSM + 10 RSSM ration significantly lower than that score for RSM dark meat. Broilers fed the RSM + 10 RSSM ration produced cooked dark meat which was slightly undesirable and which differed significantly from chickens raised on the SBM ration. The dark meat from chickens fed all rations was rated acceptable to moderately desirable. There were no significant differences in tenderness and juiciness of light meat attributable to ration.These studies indicate that feeding rations containing 10% Tower RSM to broilers did not affect the palatability of the resulting cooked chicken. Inclusion of 10% RSSM resulted in dark meat which was slightly less desirable than that from SBM chickens.

Acute Themal Stressors and Synthesis of Antibodies in Chickens ,

Three experiments utilizing 368 chickens were conducted to determine the effect of acute heat and cold stress on antibody (Ab) production to sheep red blood cells (SRBC). All birds were injected with 1 ml of a 7% suspension of SRBC within 24 hr of initiation of the themal stress. Each experiment used the same heat and cold stress regimen: four 30-min exposures to thermal treatments during four consecutive hours. In the first experiment, 40 five-week-old Hubbard broilers were either heat-stressed at an air temperature of 42 C or held at an ambient temperature of 24 C. While no differences (P>.10) were observed, antibody titers (log2; χ̄ ± SE) on day 5 after antigen injection were 10.12 ± .24 and 9.41 ± .24 for the control and heat-stressed birds, respectively. In the second experiment, 41 nine-week-old Hubbard broilers were held at air temperatures of 42 C or 26 C. No differences (P>.10) were observed in either total titers, 2-mercaptoethanol (ME) sensitive, or ME-resistant Ab titers. In Experiment 3, 72 chicks from each of the Athens Randombred, New Hampshire and White Leghorn breeds, and Hubbard broilers were acutely heat-stressed (41 C), cold-stressed (6 C), or maintained at 24 C. There were no differences (P>.10) in Ab titers among treatment groups. In contrast to previous reports, these data indicate that an acute, intermittent heat, or cold stress does not significantly alter the ability of several commercially available breeds of chickens to synthesize antibodies to sheep red blood cells. The effect of chronic themal stressors on the immune system of poultry remains unknown.

Influence of Low Glucosinolate (cv. Tower) Rapeseed Meal on the Eating Quality of Broiler Chickens. II. Subjective Evaluation by a Consumer Panel

The eating quality of eight-week-old White Mountain X Hubbard broiler chickens fed four commercial-type rations was evaluated by 146 consumer households. The rations were: a soybean meal control ration (SBM), a 20% Tower rapeseed meal ration (RSM), a soybean meal ration with 5% herring meal, .1% DL methionine, and .05% choline chloride (SBMHM), and a 20% Tower rapeseed meal ration with 5% herring meal, 1% DL methionine, and .05% choline chloride (RSMHM). Participants received four coded frozen half-chickens (one representing each ration treatment) and were instructed to cook each defrosted chicken half. Consumer panelists scored the odor, flavor, and overall acceptability of the chickens and then ranked the chickens in order of preference. Generally chickens fed the RSM ration received scores that were similar to those of comparable samples from chickens fed the SMB ration. The odor intensity of chicken representing the RSM treatment was rated lower (P<.05) than that of SMB chickens. Chickens raised on the RSMHM diet also received palatability scores which were similar to those for chickens fed the control ration or the ration containing 20% Tower rapeseed meal. Chickens fed the SBMHM ration received significantly lower odor intenstiy and flavor (intensity and like/dislike) scores than chickens fed the SBM ration. These findings suggest that the eating qualtiy of chickens was not affected by the inclusion of 20% Tower rapeseed meal in the rations. Inclusion of 5% herring meal along with supplemental methionine and choline in the SMB ration resulted in chickens with slightly lower eating quality scores, but the meat was judged to be acceptable in eating quality.

Influence of Low Glucosinolate (cv. Tower) Rapeseed Meal on the Eating Quality of Broiler Chickens. I. Subjective Evaluation by a Trained Test Panel and Objective Measurements

White Mountain X Hubbard broiler chickens were fed one of four rations: a soybean meal control ration (SBM); a 20% Tower rapeseed meal ration (RSM); a soybean meal ration with 5% herring meal, .1% DL methionine, and .05% choline chloride (SBMHM); or, a 20% Tower rapeseed meal ration with 5% herring meal, .1 % DL methionine, and .05% choline chloride (RSMHM). At eight weeks of age, chickens from each ration treatment were killed, eviscerated, and frozen for later evaluation. Cooked light and dark meat and broth samples were evaluated subjectively. Objective measurements were also made.Results obtained indicated that inclusion of 20% Tower rapeseed meal in the ration (RSM ration) did not affect the eating quality of the cooked chicken meat. However, broth prepared from chickens fed the RSM ration was rated significantly more rancid in odor, less chickeny in flavor, and lower in overall acceptance than comparable scores for broth from chickens fed the SBM ration.Inclusion of 5% herring meal along with DL methionine and choline chloride in rations for chickens resulted in significantly lower odor and overall acceptance scores in light meat, while dark meat received less chickeny, slightly fishy odor and flavor scores as well as lower acceptability scores than comparable samples fed the control diet. Generally odor, flavor, and acceptability scores for broths representing the RSMHM treatment differed significantly from comparable scores for SBM ration broths.Light and dark meat samples from chickens fed the SBMHM diet were generally similar to those samples from chickens fed the RSMHM ration. However, judges rated the flavor of dark meat from chickens fed the SBMHM ration significantly lower than that of RSMHM dark meat. Broths prepared from chickens raised on the SBMHM ration differed significantly from SBM ration broths. There were no significant differences in tenderness (taste panel data and Warner Bratzler shear) and juiciness (panel scores and water holding capacity) of light meat attributable to ration.These studies provide evidence that feeding a ration containing 20% Tower rapeseed meal (RSM ration) to broiler chickens does not affect the eating quality of the meat. The addition of 5% herring meal along with a high level of methyl groups to rations for broilers (RSMHM and SBMHM rations) may decrease the palatability of the resulting cooked chicken.

The mechanism of increasing l-asparaginase activity in the rat liver, chick liver and chick kidney

1. 1. The increase in l-asparaginase specific activity in liver of Sprague-Dawley Rats, Rattus norvegicus, and liver and kidney of Hubbard broiler chicks, Gallus domesticus, fed 75% protein diets or fasted was examined using kinetic studies. 2. 2. The 2.6-fold increase in asparaginase specific activity in liver of rats fed 75% protein diets was dependent upon a 6.8-fold elevation of the asparaginase synthesis rate. 3. 3. The 3.1-fold increase in asparaginase specific activity in liver of chicks fed 75% protein diets was due to a 3-fold reduction in the asparaginase degradation rate constant. 4. 4. The increase in asparaginase specific activity in the kidney of chicks fed high protein diets or fasted is due to an increase in the synthesis rate for asparaginase.

Accumulation and Depletion of Zinc in Chick Tissue Metallothioneins

Two experiments were conducted with Hubbard broiler chicks on the metabolism of high levels of dietary zinc. In the first experiment, chicks were fed a basal diet or the basal diet plus 500, 1,000, 2,000 or 4,000 ppm zinc, and in the second experiment chicks were fed the basal diet or the basal diet plus 1,000, 2,000, 4,000, 8,000 or 16,000 ppm zinc, using zinc acetate. Zinc was found to be associated with 4 peaks when the cytosols from tissues (liver, kidney, pancreas and intestinal mucosa) were eluted through columns of G-75 Sephadex. Although the zinc content of all four peaks increased with increased zinc content of the diet, the greatest elevation occurred in metallothionein (MT). This protein was purified from all four tissues (liver, kidney, pancreas and intestinal mucosa) and the amino acid analysis revealed the presence of about 30% cysteine. Zinc accumulated to the greatest extent (microgram in MT/g tissue) in MT of the pancreas. The zinc in MT disappeared very rapidly when chicks which had been fed a diet containing high levels of zinc were fed a low zinc diet, indicating the extreme lability of this metal in this protein. The results suggest the involvement of MT in zinc homeostasis.

Influence of Rapeseed Meal on the Eating Quality of Chicken. II. Subjective Evaluation by a Consumer Taste Panel

The eating quality of eight-week old White Mountain × Hubbard broiler chckens fed three commercial-type rations was evaluated by 144 consumer households. The rations were: a soybean meal control ration (SBM), a 15% Span rapeseed meal ration (RSM), and a 15% Span rapeseed meal ration with 5% herring meal, .1% methionine, and .05% choline chloride (RSMHM). The consumers received three coded frozen half-chickens (one representing each ration treatment) and were instructed to cook each defrosted chicken half. Consumer panelists scored the odor, flavor, and overall acceptability of the chickens using a five-point hedonic scale and then ranked the chickens in order of preference. Subjective evaluation by the consumer panel indicated that chickens fed the RSMHM ration received significantly lower odor, flavor, and overall acceptability scores than chickens fed either the SBM or RSM rations. Chickens representing the RSM ration received slightly lower palatability scores than SBM chickens, but the differences were not significant. Preference ratings indicate that chickens fed the RSMHM ration were rated as “least preferred” more frequently (P<.05) than chickens fed either the SBM or RSM rations, which received similar ratings. These findings suggest that the eating quality of chickens was adversely affected by feeding the RSMHM. Inclusion of 15% Span rapeseed meal in the ration (RSM), resulted in chicken which was judged acceptable in eating quality.

Influence of Rapeseed Meal on the Eating Quality of Chicken I. Subjective Evaluation by a Trained Taste Panel and Objective Measurements

White Mountain × Hubbard broiler chickens were fed one of four rations: a soybean meal control ration (SBM); a soybean meal ration with a high fat and fiber content (SBMF); a 15% Span rapeseed meal ration (RSM); or, a 15% Span rapeseed meal ration with 5% herring meal, .1% DL methionine, and .05% choline chloride (RSMHM). At eight weeks of age, chickens from each treatment were commercially killed, eviscerated, and assigned to one of three storage periods: fresh, 18 days frozen storage, or 6 months frozen storage. Cooked light and dark meat and broth samples were evaluated subjectively. Objective measurements were also made.Results obtained indicate that: 1) feeding the RSMHM ration caused significantly lower scores for the odor, flavor, and overall acceptability of samples of light and dark chicken meat and broth than scores for comparable samples from chickens fed the other three rations, 2) inclusion of 15% Span rapeseed meal in the ration (RSM ration) resulted in significantly lower flavor and overall acceptability scores for dark meat samples and flavor scores for broth samples than comparable scores for dark meat and broth from chickens fed the SBM (control) ration, 3) tenderness scores for light and dark meat from chickens fed the RSMHM ration were significantly lower than tenderness scores for comparable samples from SBM chickens, however, shear force values were not significantly affected by ration treatment, 4) there were no significant differences in juiciness attributable to ration (taste panel data) and water holding capacity (WHC, 5) trained panelists indicated that, except for odor scores for light meat, dark meat, and broth samples and juiciness scores for light meat samples, broiler eating quality was not affected by frozen storage, 6) light meat samples from chickens held frozen for six months required less shear force than fresh or short frozen chickens, and 7) WHC of frozen chickens stored 6 months was significantly lower than WHC of fresh chickens.