Effects of bird density on Salmonella contamination of prechill carcasses

Two similar trials were conducted to evaluate the effects of bird density on Salmonella contamination of processed broilers. Commercial strain broiler chicks were reared in floor pens on new litter at densities of 557, 619, 697, 796, 929, and 1,115 cm2 per bird. Twenty percent of the chicks in each density were gavaged directly into the crop with .5 mL of 10(8) nalidixic-acid-resistant (NAR) Salmonella typhimurium on Day 2. Twenty percent of the uninoculated birds in each density category were processed at 42 days. Prechill carcasses were evaluated for NAR Salmonella incidence using the whole carcass rinse technique and a mechanical shaking device. The resulting NAR Salmonella contamination rates (from lowest to highest bird densities) were as follows, 55, 4.2, 35.7, 34.3, 88.9, and 20% in Trial 1; and 30, 20.8, 28.6, 50, 58.3, and 30% in Trial 2. A random sample of the prechill carcasses of gavaged birds indicated a contamination rate of 13.8% in Trial 1 and 61.1% in Trial 2. The NAR Salmonella contamination rates of the prechill carcasses did not appear to be affected by the bird densities evaluated in these trials. Feed intake and body weight at 42 days were adversely affected by the highest bird density, but feed utilization was not affected.

Effects of dietary lactose on incidence and levels of salmonellae on carcasses of broiler chickens grown to market age

Two trials were conducted to evaluate the effects of lactose in the diet of broilers grown to market weights on incidence and levels of salmonellae on the carcass. Lactose was substituted for sand in otherwise nutritionally complete diets at levels of 0, 2.5, 5, and 7.5% and fed from day-old to 49 days of age. Birds were reared on used (Trial 1) or new (Trial 2) litter and inoculated via the drinking water on Days 2, 7, and 14 with 10(8) cfu/mL Salmonella typhimurium (ATCC 14028). At 50 days, 12 (Trial 1) or 24 (Trial 2) birds per treatment were processed and prechill carcasses were evaluated for salmonellae incidence and level by the most probable number (MPN) method. Body weight of male broilers was significantly reduced by feeding diets containing up to 7.5% lactose. Feed intake of broilers fed diets containing lactose was significantly reduced and feed utilization improved, suggesting that lactose provided some metabolizable energy. The degree of litter caking was significantly increased, and cecal pH was significantly decreased as dietary lactose increased. Prechill carcases of broilers fed diets with 7.5% lactose had significantly higher levels of salmonellae than did prechill carcasses of broilers fed 0% lactose. The results of the present study suggest that supplementing poultry diets with lactose is not a viable means in itself of reducing or eliminating salmonellae incidence or levels on processed broiler carcasses.

Effect of dietary protein level and length of feeding on performance and abdominal fat content of broiler chickens

Dietary CP levels influence carcass fat content of chickens but the length of time necessary to feed higher levels in order to increase carcass fat is not known. Studies were conducted to evaluate the effects of length of feeding of different levels of dietary CP on broiler performance and abdominal fat deposition. All diets were calculated to be isocaloric at 3,200 kcal ME/kg. Broilers fed 23% CP for 0 to 21 days, 20% CP for 21 to 42 days, and 18% CP for 42 to 49 or 42 to 56 days served as the control group in each of two trials. In the first trial, broilers were fed constant levels of CP from day-old to market age with CP levels ranging from 15 to 27% (amino acids adjusted in proportion to CP level). Other broilers were fed 23% CP for 0 to 21 days and then fed either 15, 17, 19, or 21% CP to market age. In the second trial, broilers were fed constant levels of CP (18, 20, or 23%) from day-old to market age. Feeding CP levels lower than those fed the control group had a more pronounced effect on males than on females, with the primary effects being reduced body weight, poorer feed utilization, and increased carcass fat content. Feeding CP levels higher than those fed the control group generally did not increase final body weight but generally improved feed utilization and decreased carcass fat content. The economics of improved feed utilization and reduced carcass fat must be considered in determining dietary CP levels to use at different ages for growing broilers.

Comparison of different anticoccidials on processing characteristics and parts yield of broiler chickens

Broilers were grown to 42 days of age on diets supplemented with salinomycin (60 mg/kg), monensin (99 mg/kg), or halofuginone (3 mg/kg) and continued on unmedicated diets to 49 days of age. There were no significant (P greater than .05) differences among anticoccidials in final body weight, feed conversion, or mortality rates. Samples of birds were processed for dressing percentage and parts yield. Both males and females fed salinomycin had significantly higher breast meat yield as a percentage of postchill weight than those fed halofuginone but not those fed monensin; differences were not significant for breast meat yield of males or females fed monensin or halofuginone. Males fed halofuginone had significantly heavier leg quarters than those fed salinomycin but not those fed monensin. Females fed salinomycin had significantly higher water uptake during chill than those fed monensin or halofuginone. Results of the present study indicate that the anticoccidial used in growing broilers may influence some carcass yield parameters.

Research note: fumaric acid enhances performance of broiler chickens

Two studies were conducted to examine the effects of dietary inclusion of fumaric acid on performance and carcass composition of broiler chickens. Fumaric acid was added to nutritionally complete diets at levels of 0, .125, .25, and .5% and fed from 1 to 49 days under simulated commercial conditions. In one trial, samples of birds were processed to determine dressing percentage and abdominal fat content. In the first trial (mixed sex broilers), the addition of .125% fumaric acid significantly (P less than .05) improved 49-day body weight of females and average weight gain of both sexes with no effect on feed utilization. Feed consumption was significantly increased when diets contained .125 or .50% fumaric acid. In the second trial (male broilers), 49-day body weight was significantly (P less than .05) improved by the addition of .125 and .25% fumaric acid. There were no significant differences in feed consumption; feed utilization was improved by the addition of all levels of fumaric acid. Dietary fumaric acid had no adverse effects on dressing percentage, abdominal fat content, or mortality rate.

Effects of dietary amino acid levels on performance and carcass composition of broilers 42 to 49 days of age

Broilers were grown to 42 days on nutritionally complete diets. From 42 to 49 days in two trials, broilers were fed diets formulated to contain 70, 80, 90, 100, 110, or 120% of recommended amino acid (AA) values. In four additional trials, the same AA levels were fed; in addition, Met and Lys were added to diets formulated to contain 70, 80, and 90% to equal levels of the 110% AA diet. Body weight gain (BWG), feed consumption (FC), feed conversion (FCR), dressing percentage (DP), and abdominal fat (AF) were measured. From 42 to 49 days, dietary AA levels had little effect on BWG, DP, or AF of female broilers. When male broilers were fed diets containing less than 100% of the recommended AA levels, BWG was reduced and AF increased. Broiler FC increased and FCR decreased as the AA level of the diet decreased. The addition of Met and Lys to the 90% AA diet improved performance; however, the addition of Met and Lys to the 70% AA diet had no beneficial effect. Amino acid levels may be reduced in broilers diets fed from 42 to 49 days; however, male broilers are more sensitive than females to reductions in AA levels during this period.

Effects of dietary amino acid levels on bone development in broiler chickens

Studies with several species suggest that dietary protein may influence bone calcification. Six pens of six male broilers in two consecutive trials were fed from 1 to 21 days either .5 or 1.0% Ca in diets with 80, 90, 100, 110, or 120% of the amino acid (AA) standards suggested by Thomas et al. in 1986 at a constant .46% nonphytate P. The BW and feed conversion rate (FCR) were determined, and bone measurements were taken. Both AA and Ca levels influenced BW with an interaction of the two factors. The Ca level, but not AA level, influenced FCR. The lower Ca level inhibited feed intake. Increasing AA levels reduced bone ash but did not affect tibia breaking strength. There was an interaction of AA and Ca on tibia ash, tibia weight, and tibia length. The higher AA levels supported normal linear growth of the tibia but decreased rate of calcification, especially in the diets with .5% Ca. In diets with marginal Ca levels, higher AA levels may reduce bone calcification.

Efficacy of different anticoccidials against experimental coccidiosis in large white turkeys

Two trials were conducted to compare the efficacy of currently approved anticoccidials for turkeys against challenge using a field isolate of mixed Eimeria species; E. adenoides, E. gallopavonis, and E. meleagrimitis. Poults in wire-floored cages were fed unmedicated diets from day-old to 3 wk of age. Diets were supplemented with either amprolium (AMP, 125 mg/kg), butynorate (BUT, 375 mg/kg), monensin (MON-60, 60 mg/kg; MON-100, 100 mg/kg), halofuginone (HAL; 3 mg/kg), zoalene (ZOA; 125 mg/kg), or sulfadimethoxine plus ormetoprim (SUL + ORM, 62.5 mg/kg and 37.5 mg/kg, respectively). After 2 days on the test diets, poults were individually weighed and inoculated with sporulated coccidial oocysts from the field isolate. Total fecal collections were obtained for Days 0 to 5 and 6 to 10 to estimate oocyst output. At 10 days postinoculation, the birds were individually weighed and killed to determine severity of intestinal lesions. The HAL and MON were most effective and AMP, ZOA, and SUL + ORM were least effective in maintaining weight and in reducing the severity of intestinal lesions. All the coccidiostats tested reduced oocyst passage, but poults fed HAL produced fewer oocysts. The results demonstrated differences in efficacy among anticoccidials with the more recently approved drugs providing the best protection against coccidiosis.

Effects of different coccidiostats on performance of large white turkeys

Two trials were conducted to evaluate the effects of feeding various anticoccidial products to turkeys to 8 wk and then growing to market age (16 wk for hens and 20 wk for toms). Anticoccidials evaluated in the first trial included amprolium at 187.5 mg/kg for 0 to 4 wk and 125 mg/kg for 4 to 8 wk; butynorate at 375 mg/kg for 0 to 8 wk; monensin at both 60 (MON-60) and 100 mg/kg for 0 to 8 wk; zoalene at 187.5 mg/kg for 0 to 4 wk and 125 mg/kg for 4 to 8 wk; and halofuginone at 3 mg/kg for 0 to 8 wk. In the second trial, MON-60 was replaced by a combination of sulfadimethoxine (62.5 mg/kg) plus ormetoprim (37.5 mg/kg) for 0 to 8 wk. In each trial each treatment was fed to four pens of 16 hens and four pens of 12 toms. Several of the anticoccidials significantly influenced the weight of both hens and toms by producing lower weights at the end of the 8-wk feeding period than birds in other treatments. However, after removal of the anticoccidials, compensatory gains were observed in almost every instance. Significant effects of previous anticoccidial feeding were noted on body weight of hens at 16 wk but not on weights of toms at 20 wk.

Effects of formic acid or calcium formate in feed on performance and microbiological characteristics of broilers

Three experiments were conducted to determine the effects of feeding broilers formic acid (FA) or calcium formate (CF) on performance and microbiological characteristics of broilers. Live bird performance was not adversely affected by feeding up to 1.0% FA or 1.45% CF. In Experiment 1, levels of salmonellae in carcass and cecal samples were significantly reduced by feeding birds .36% CF. Salmonellae were not isolated from any of the carcasses of birds fed .36% CF. Similar reductions were not noted for total organisms or presumptive coliforms. In Experiment 2, feeding .36% CF nonsignificantly reduced levels of salmonellae in carcass and cecal samples, but again, levels of total organisms and coliforms were not reduced. In Experiment 3, salmonellae in the ceca or in the carcass rinse fluid were not reduced by feeding .36% CF.

Effects of different antibiotics on performance, processing characteristics, and parts yield of broiler chickens

Broilers were grown to 49 days of age on diets supplemented with bambermycins (BAM, 2.2 ppm), bacitracin methylene disalicylate (BMD, 27.5 ppm), virginiamycin (VM, 11 ppm), or an unmedicated control. Samples of birds were processed for dressing percentage and parts yield. There were no significant (P greater than .05) effects of antibiotics on final body weight, feed conversion, or mortality. In male broilers, BMD and VM significantly (P less than or equal to .05) increased dressing percentage and percentage yield and reduced the skeletal rack as a percentage of postchill weight compared to those fed the nonmedicated control. All antibiotics significantly increased breast skin weight and breast skin as a percentage of postchill weight of as compared with those fed the unmedicated control. In female broilers, BAM and BMD significantly increased dressing percentage and percentage yield and increased breast weight and breast as percentage of postchill weight as compared with those fed the unmedicated control diet. Females fed BMD also had significantly heavier leg quarters and breast skin than those fed the unmediated control. Females fed VM had increased breast skin weight and breast skin as a percentage of postchill weight than those fed the unmedicated control. The results of the present study indicate that antibiotics may influence dressing percentage and parts yield in the absence of improvements in body weight gain or feed utilization.

The effects of energy and amino acid levels on performance and carcass quality of male and female broilers grown separately

Studies were conducted to evaluate the response of male and female broiler chickens to diets containing different levels of energy and amino acids. Two energy series were compared: 3,080, 3,135, and 3,190 kcal of ME/kg ("low") and 3,190, 3,245, and 3,300 kcal of ME/kg ("high") in pelleted starter, grower, and finisher diets. Diets provided a minimum of 85, 90, 95, 100, 105, and 110% of suggested amino acid recommendations for the broiler male except for Met and TSAA, which were kept at 105%. Modifications were made in feeding periods, recognizing the differences in rate of gain and marketing ages of the two sexes. Feeding periods were 0 to 21, 21 to 42, and 42 to 56 days for males and 0 to 18, 18 to 35, and 35 to 49 days for females. Four floor pen trials utilizing 9,600 male and 9,600 female broilers were conducted. Birds were processed to determine dressing percentage and abdominal fat pad weights. Energy content of the diets had no significant (P greater than .05) effect on body weight or feed efficiency for male or female broilers. Carcass dressing percentage of females, but not males, was significantly (P less than .05) increased on the high energy series. Abdominal fat pad was not influenced by energy for either sex. For both sexes, increasing dietary amino acid levels resulted in significant (P less than or equal to .05) linear improvements in live weights and feed utilization and a reduction in abdominal fat pad weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of feeding lasalocid on performance of broilers in moderate and hot temperature regimens

Three trials were conducted in environmental chambers to study the effects of feeding lasalocid on broiler performance. Birds were randomly assigned at 31 or 35 days of age to one of four treatment groups: hot cyclic (26.7 to 37.8 C and 90 to 40% RH) with basal diet; hot cyclic with lasalocid diet (88 mg/kg); moderate constant (21 C and 50% RH) with basal diet; or moderate constant with lasalocid diet. All birds were killed and processed 2 wk after the start of each trial. Percentage of carcass yield and fat pad weight were determined. In the moderate temperature regimen, lasalocid feeding caused a depression in the 2nd wk gain (469 versus 486 g) but not in the final 2-wk gain. In the hot temperature regimen, birds fed lasalocid gained significantly more weight in the 2nd wk than those fed the basal diet (341 g versus 325 g) and had a significantly better feed conversion in the 2nd wk (2.04 versus 2.61) and overall (2.07 versus 2.32) than those fed the basal diet.

The effect of zinc bacitracin and roxarsone on performance of broiler chickens when fed in combination with narasin

Six trials were conducted at various locations to determine the response of broiler chickens to combinations of zinc bacitracin and roxarsone when fed in the presence of narasin. The addition of zinc bacitracin at 55 mg per kg significantly improved growth rate and feed utilization when data from all locations were combined. There was no effect of roxarsone fed at 50 mg per kg on BW or feed utilization, nor was there an interaction of roxarsone and zinc bacitracin on BW. There was a significant interaction of roxarsone and zinc bacitracin for feed utilization; addition of zinc bacitracin significantly improved feed utilization both in the presence and absence of roxarsone, but the improvement was greater in the absence of roxarsone.

Effects of a buffered propionic acid in diets on the performance of broiler chickens and on microflora of the intestine and carcass

A buffered propionic acid (BPA) was added to broiler diets fed in floor pens with litter. The BPA was fed continuously at 0, .2, .4, and .8% in Trial 1 and at 0 and .4% in Trial 2. The BPA was also fed at .4% for the last 7 days in Trial 2. Natural salmonellae exposure versus periodic dosage with Salmonella typhimurium was compared in Trial 2. In Trial 1, the BPA supplement had no adverse effects on growth, feed utilization, or abdominal fat with a significant (P less than or equal to .05) increase in the female dressing value at .8% of buffered propionic acid. The total number of coliforms and of Escherichia coli in the duodenum were significantly reduced by .4% BPA; in the jejunum, by all levels used in the trials; and in the ileum, by .4% and .8% of buffered propionic acid. The intestinal pH was not influenced by the BPA addition. In Trial 2, the BPA at .4% fed continuously had no adverse effect on growth, feed utilization, the abdominal fat of females, or the dressing percentage of males while significantly reducing the abdominal fat for males and increasing the dressing percentage for females. Feeding .4% BPA for the last 7 days had no effect on any of these parameters. Periodic dosage with S. typhimurium had no effect on body weight, feed utilization, or abdominal fat and significantly increased the dressing percentage. There was a significant interaction between the Salmonella dosage and the time of feeding BPA on dressing percentage.(ABSTRACT TRUNCATED AT 250 WORDS)

Production and Processing Studies to Reduce the Incidence of Salmonellae on Commercial Broilers 1, 2

A series of experiments have been conducted at the University of Arkansas over the last two years in efforts to decrease the incidence of salmonellae on commercial broilers. These experiments have concentrated on feeding trials in efforts to alter intestinal microflora, and processing trials in which chemical additives have been evaluated. A buffered propionic acid compound was fed at various concentrations for specific time periods and the cecal tonsils, small intestine, litter, and processed carcasses were tested for salmonellae and other organisms. In a separate series of trials a variety of chemicals were added to the scald, chill, scald and chill, or used as pre- or post-chill dips or sprays in efforts to decrease carcass contamination with salmonellae and extend product shelflife. Feeding trials indicate that the addition of a buffered propionic acid can alter intestinal microflora and decrease contamination of the processed carcass without adversely affecting live bird performance. Processing trials indicate that certain chemicals such as lactic acid can be used in a variety of ways to either decrease or eliminate salmonellae from the carcass and extend shelflife of processed broilers. However, some chemicals at high concentrations may produce undesirable organoleptic characteristics.

Effects of ethoxyquin feed preservative and peroxide level on broiler performance

Rancidity development in feeds and feed ingredients reduces the feeds' nutritive value and produces toxic peroxides. This investigation was conducted to determine the effects of different levels of peroxide on broiler performance and to determine the effectiveness of ethoxyquin in ameliorating the adverse effects of peroxides. Poultry fat was oxidized to contain 0, 50, 100, and 175 meq peroxide/kg and added to diets to provide 0, 2, 4, or 7 meq peroxide/kg feed, respectively. Liquid ethoxyquin was incorporated into the diets at 0, 62.5, and 125 ppm. Each of the 12 diets was fed to 8 replicate pens with 35 males and 35 females/pen. Body weights at 21 and 42 days of age were significantly lower in birds fed diets containing 4 or 7 meq peroxide/kg feed. At 49 days of age, the reduction in body weight was significant only at the 7 meq/kg level. Reductions in feed efficiency showed a similar pattern, but the depression was significant only at the highest peroxide level. Supplementation of 62.5 and 125 ppm ethoxyquin resulted in significantly heavier birds at 49 days of age but had no significant effect on feed efficiency. Beneficial effects of ethoxyquin supplementation were evident at higher peroxide levels. The study showed that at least 4 meq peroxide/kg feed was required to significantly affect bird performance, and that the addition of ethoxyquin could alleviate the deleterious effects of dietary peroxide.

Estimation of the tryptophan requirement of male broiler chickens

Three experiments were conducted to determine the response of the male broiler chick to tryptophan (TRP) supplementation. Chicks were fed from 7 to 18 or 7 to 20 days posthatch either a grain sorghum-soybean meal diet containing .16% TRP, supplemented with 0, .02, .04, .06, .09, or .11% L-TRP, or a corn-soybean meal positive control diet containing .25% TRP. Levels of TRP in all diets were confirmed by ion-exchange chromatography using an alkaline hydrolysis. The test diet contained 15.34% CP (N x 6.25) from intact ingredients and 20% CP (N x 6.25) when supplemented with other amino acids to 110% of National Research Council recommendations in 1984. No improvement in gain or feed efficiency was observed with chicks fed the grain sorghum-soybean meal diet at any level of TRP supplementation. Feed utilization but not weight gain of the chicks fed the TRP-supplemented test diets was significantly poorer than that of chicks fed the corn-soybean meal positive control diets. These results suggest that the TRP requirement of the young (0 to 21-day-old) broiler chicken is no greater than .16% of a diet containing 3,200 kcal ME/kg.

Ascorbic acid and acetylsalicylic acid (aspirin) in the diet of broilers maintained under heat stress conditions

Male broiler chicks were grown to 21 days of age under normal conditions, then placed in environmental chambers maintained under constant (24 C) or cyclic (24 to 35 C) heat conditions. Chicks were acclimated for 1 wk on a standard grower basal diet. Standard grower basal diets were fortified with 0, 125, 250, 500, or 1,000 ppm coated ascorbic acid (AA) or 0, 125, 250, or 500 ppm acetylsalicylic acid (ASA). Test diets were fed for 14 days in two separate studies. Cyclic heat conditions reduced feed intake and significantly reduced weight gains in both trials. Feed efficiency was not significantly affected by heat stress. Neither AA or ASA had beneficial effects on broiler growth or feed efficiency.

Use of organic acids in broiler diets

Two feeding trials were carried out to determine the potential use of fumaric acid and calcium formate in diets for broiler chickens. In the first study using male broiler chicks fed to 21 days of age, fumaric acid was added at 0, .5, 1.0 and 1.5% and calcium formate was added at 0, .72, 1.48, 2.20, and 2.89%. All combinations of fumaric acid and calcium formate were evaluated in a 4 x 5 factorial arrangement of treatments. Addition of .5 or 1.0% fumaric acid significantly (P less than .05) improved body weights of broilers but did not influence feed utilization. Addition of calcium formate at levels greater than .72% significantly reduced both body weight and feed utilization. There was no significant interaction between levels of fumaric acid and calcium formate. In a second trial, male and female broiler chicks were grown to 49 days of age using diets containing 0, .5, 1.0, and 1.5% calcium formate. Addition of .5 or 1.0% calcium formate had no significant effect on weight gains or feed utilization. Addition of 1.5% calcium formate significantly reduced body weights of both males and females at 21 and 42 days. At 49 days of age, body weights of males fed 1.5% calcium formate did not differ from those of males fed the control diet, but were significantly less than those of males fed diets with .5 or 1.0% calcium formate. Female body weights at 49 days of age were significantly depressed by addition of 1.5% calcium formate.

Performance and yields of broilers fed extruded grain amaranth and grown to market weight

A trial was conducted to determine the effects of feeding extruded grain amaranth (Amaranthus cruentus) on performance of male broilers grown in batteries to 49 days of age. Practical corn-soy rations were supplemented with 0, 10, 20, 30, 40, or 50% amaranth and formulated to meet nutrient requirements for the starter (0 to 21 days), grower (21 to 42 days), and finisher (42 to 49 days) periods. Each diet was fed to six replicate pens of 10 male birds each. No differences were observed for feed utilization (P greater than .05), but at Day 49, birds fed 50% amaranth weighed significantly less and had significantly lighter dressed carcass weights than those fed the control diet. For dressing percentages, no significant differences among diets were observed. Dietary differences in fat pad weights were not detected, but significant differences between diets were observed for fat pad weights expressed as a percentage of the total carcass weight (% OTC). Significant and positive linear responses existed when liver weight, liver weight as % OTC, and fat pad weight as % OTC were regressed upon amaranth inclusion. No treatment differences were observed for heart or pancreas weights or for their weights as % OTC. Gizzard weight and gizzard weight as % OTC decreased linearly with amaranth inclusion. Giblet weights (heart + liver + gizzard) were significantly different among diets, but giblet weight appeared to be unrelated to amaranth level. Birds fed the diet with 50% amaranth had giblets of equal size to birds fed the control diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of extruded grain amaranth as a feed ingredient for broilers. 2. Apparent amino acid availability values

Apparent amino acid availabilities (AAAA) were determined for grain amaranth in two experiments using broilers. Total collection method (TCM) and acid-insoluble ash (AIA), as a marker, were used for these determinations. Individual amino acid availabilities for the extruded grain were calculated both by regression analysis and by difference from the basal diet. From the linear regression equations, TCM produced more accurate results than did the AIA method, based on standard errors of the intercept and coefficient of determination. Predicted AAAA, based on linear regression equations, from the TCM were 92.4, 79.9, and 89.4% for methionine, lysine, and arginine, respectively. Using the TCM and calculation by difference, average AAAA on an as-fed basis were 85.0, 79.1, and 92.9% for methionine, lysine, and arginine, respectively. The AAAA of 11 other amino acids were also determined.

Assessment of extruded grain amaranth as a feed ingredient for broilers. 1. Apparent metabolizable energy values

Two trials were conducted to determine the apparent metabolizable energy (AME) and nitrogen-corrected AME (AMEn) of extruded grain amaranth (Amaranthus cruentus). Procedures for these determinations were the total collection method (TCM) and the use of acid-insoluble ash (AIA) as a marker. The AME and AMEn values for the grain were determined both by regression analysis and by calculations based on differences from the basal diet. Based on standard errors of the predicted values and coefficients of determination of the regression equations, TCM produced more accurate results than did AIA. Using regression analysis, the predicted values from the TCM were 3,382 kcal/kg of AME and 3,267 kcal/kg of AMEn on an as-fed basis. When expressed on a dry-matter basis, these values were 3,646 and 3,522 kcal/kg for AME and AMEn, respectively. When the difference method was used to calculate the ME of the extruded grain on an as-fed basis, the values of 3,295 kcal/kg of AME and 3,164 kcal/kg of AMEn were obtained. When the results were expressed on a dry-matter basis, 3,556 kcal/kg of AME and 3,415 kcal/kg of AMEn were determined.

Feather meal as a nonspecific nitrogen source for abdominal fat reduction in broilers during the finishing period

Earlier studies have shown that excessive abdominal fat deposition in broilers can be overcome by feeding feather meal (FM) during the finishing period (7 or 14 days prior to slaughter). Studies were conducted to determine if the observed fat reduction in FM-fed birds was due to factors other than supplying excess protein. The FM was added at levels of 4, 6, and 8% and glycine at levels of .125, .25, and .5%, similar to amounts contributed by corresponding levels of FM. Corn-soybean diets were also formulated at protein levels corresponding to those of FM diets. All experimental diets were fed from 35 to 49 or from 42 to 49 days of age. There were no significant differences in weight gain and feed efficiency of treatment and control groups during the study. The addition of glycine resulted in a significant (P less than .05) reduction in abdominal fat content and appeared to be partially responsible for the observed reduction in FM-fed birds. Increasing the dietary protein level also significantly (P less than .05) reduced abdominal fat deposition regardless of protein source. The study indicates that lower quality protein sources such as FM can be effectively used as a nonspecific nitrogen source for reducing abdominal fat deposition during the finishing period.

Response of broiler chickens to dietary supplementation with roxarsone and bacitracin methylene disalicylate in diets containing narasin

Six trials were conducted at different locations to examine the response of broiler chickens to roxarsone and bacitracin in the form of bacitracin methylene disalicylate (BMD) in the presence of the anticoccidal narasin. All diets contained narasin (80 mg/kg) and were fortified with a factorial arrangement of roxarsone (0 to 50 mg/kg) and BMD (0 or 55 mg/kg). Broilers were grown to market weights with narasin and roxarsone removed from the diets for the final 5 days. Addition of both roxarsone and BMD resulted in significant (P less than .05) improvements in body weight and feed utilization. Response to roxarsone for feed utilization was influenced to some extent by the presence or absence of BMD. Although the response to roxarsone was always positive, the degree of response was lessened by the presence of BMD. This resulted in a significant (P less than .10) interaction between roxarsone and BMD for feed utilization but not for body weight.