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: incidence, number, and serotypes of Salmonella on frozen broiler chickens at retail.

Two similar trials were conducted to evaluate broiler carcasses at retail for incidence, number, and serotypes of salmonellae. Twelve frozen carcasses were purchased from each of three retail outlets on two sampling days. Two of the brands purchased were produced and processed conventionally, but the third brand was produced and processed under organic conditions. The frozen carcasses were tempered to 4.4 C prior to microbiological sampling. All carcasses were sampled using a mechanical shaker and 100 mL of sterile water. Recovered rinse fluid was evaluated for levels of salmonellae using a three-tube most probable number technique. All recovered Salmonella isolates were serotyped using the Kauffmann-White scheme. Incidence rates across the three brands ranged from 17 to 50%, with most probable number of salmonellae per 100 mL of recovered rinse fluid ranging from 5 to 34 organisms. Serotypes recovered include Salmonella typhimurium, Salmonella paratyphi, and Salmonella arizonae.

Research note: use of consecutive carcass rinses and a most probable number procedure to estimate salmonellae contamination of inoculated broilers.

Two similar trials were conducted to evaluate the accuracy of the whole carcass rinse technique in combination with a most probable number (MPN) procedure for estimating the number of salmonellae on postchill broilers. Birds were reared in litter-floored pens and inoculated with Salmonella typhimurium (10(8) cfu/mL) on Days 2, 7, and 14. In each of the two trials six carcasses were consecutively rinsed four times. Each carcass was rinsed with 100 mL of sterile water in sterile plastic bags using an automated shaking device. Salmonellae were enumerated using a three-tube MPN procedure in selenite cystine broth. There were no statistical differences in log10 MPN salmonellae per milliliter of recovered rinse fluid due to trial or consecutive rinse. In several cases salmonellae were not recovered in the initial rinse but were recovered from consecutive rinses of the same carcass. A large amount of variation in MPN levels of salmonellae among individual carcasses occurred within each consecutive rinse. The data suggested that only a percentage of the total salmonellae present on a postchill carcass were recovered with each consecutive rinse, and the organisms were firmly attached prior to processing.

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.

Research note: evaluation of the Report Salmonella visual immunoassay for detection of salmonellae on raw poultry carcasses.

Two trials were conducted to compare the standard culture procedure and the Report Salmonella Visual Immunoassay for detection of salmonellae in rinse fluid recovered from raw poultry carcasses. Both assays were evaluated with and without preenrichment in lactose broth prior to enrichment in selenite cystine broth. Live birds were inoculated via the drinking water prior to processing to ensure a high degree of carcass contamination. Prechill carcasses were sampled using 200 mL of sterile water. Results indicated that lactose preenrichment was not necessary for salmonellae evaluation using standard culture procedures. However, the Report assay produced fewer false-negative results if lactose preenrichment was utilized.

Effect of litter condition on microbiological quality of freshly killed and processed broilers.

Two similar trials were conducted to evaluate the effects of litter condition on microbiological quality of freshly killed (feathers intact) and processed broilers. Commercial broilers were reared to 49 days of age on new or previously used litter. Birds in half of the replicate pens were inoculated with Salmonella typhimurium via the drinking water on Days 2, 7, 14, and 21. Broilers were sampled at the following processing locations: postkill, postpick, prechill, and postchill. Postchill carcasses from birds raised on previously used litter did not have significantly different aerobic plate counts, levels of coliforms, or numbers of salmonellae as compared with carcasses from birds raised on new litter. Live bird inoculation did significantly increase levels of salmonellae on the fully processed carcass.

Effects of D-mannose on incidence and levels of salmonellae in ceca and carcass samples of market age broilers.

Two similar trials were conducted to evaluate the effects of 2.5% d-mannose (DM) in the drinking water of broilers for the first 10 days on incidence and levels of salmonellae in the ceca and on the carcass at market age. Controls received drinking water with no DM. Birds were reared on used litter in floor pens and were inoculated via the drinking water with 10(8) cfu/mL Salmonella typhimurium (ATCC 14028) on Day 3. At 49 days, 60 birds per treatment were processed and the ceca contents and prechill carcass were evaluated for salmonellae incidence by the most probable number (MPN) method. Results were inconclusive: level of salmonellae in the ceca contents and carcass rinse was significantly lower in control samples than in DM samples in one of the two trials; the reverse was true in the other trial.

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)

The use of carcass halves for reducing the variability in salmonellae numbers with broiler-processing trials.

Two similar trials were conducted in order to compare the variability in the number of salmonellae between the right and left sides of individual broiler carcasses with the variability among carcasses. In both trials, the variation between carcass sides was equal and was significantly less than the variation among carcasses. For trials involving bactericidal treatment, the authors would suggest that the utilization of carcass halves (one side for control, the other for treatment) would allow for a more-sensitive evaluation of treatment effects.

Effects of Sampling Method and Feed Withdrawal Period on Recovery of Microorganisms from Poultry Carcasses 1.

Five trials were conducted to evaluate the effects of four microbiological sampling techniques for determining aerobic plate counts, presumptive coliform counts, and yeasts and mold counts of broiler carcasses. The effects of feed withdrawal period on bacterial numbers was also evaluated. Sampling methods evaluated were a surface swab technique, a whole carcass rinse procedure, a breast skin rinse procedure in which the skin was excised from the breast area, and a sample blending technique that involved breast skin excision and blending. Results from these trials indicated that the whole carcass rinse procedure yielded significantly greater recovery of aerobic mesophiles than the other methods evaluated. The recovery of coliforms was significantly greater when either the whole carcass rinse or the breast blend procedure was employed. The numbers of yeasts and molds present on the prechill carcass were extremely low, and results obtained using the various sampling methods were inconsistent. Regardless of sampling methodology and type of organism enumerated, the highest counts were obtained from broilers that had not been withdrawn from feed prior to processing.

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.

Comparison of the DNA Probe to Culture Methods for the Detection of Salmonella on Poultry Carcasses and Processing Waters 1.

In a series of five experiments a total of 269 broiler carcass and chill tank water samples were tested for the presence of Salmonella using the DNA probe and the standard cultural method. Carcasses were sampled using a whole carcass rinse technique. Samples consisted of pre- (48) and post-chill (103) carcasses, and pre-chill (48) and chill (70) tank water. Samples to be evaluated with the DNA probe were subjected to three preenrichment/enrichment procedures to determine the most accurate and reliable enrichment procedure to use with the DNA probe assay. Direct enrichment in Selenite Cystine followed by 24 h incubation in Gram Negative broth allowed for recovery of 0.03 salmonellae/ml from carcass rinse and from pre-chill water using either the standard cultural method or the DNA probe. Preenrichment in Lactose broth produced inaccurate results for pre-chill carcass and pre-chill water samples using the DNA probe assay, and may be due to extreme microbiological competition. No false positive results were obtained using the DNA probe assay for any of the four sample types.

Incidence and level of Campylobacter jejuni in broiler processing.

The distribution and level of Campylobacter jejuni throughout broiler processing was evaluated. Six trials were conducted at three broiler processing plants to determine the occurrence of C. jejuni on commercial broilers as affected by specific processing functions. Counts were determined at specific sampling stations throughout the plants, and patterns of counts among sampling stations and plants were observed. Between 1,100 and 5,500 C. jejuni/1,000 cm2 skin surface (represents half the skin surface area of one defeathered broiler) were found on birds entering the three plants. Increases in C. jejuni levels were associated with both the picking and evisceration operations. Broiler carcasses ready for packaging contained approximately 50 organisms/1,000 cm2. Campylobacter jejuni was also recovered from gizzard samples, carcass and gizzard chill water, and swab samples taken of selected equipment surfaces.

Incidence of Campylobacter jejuni in processed egg products.

Egg samples were obtained from two commercial egg-processing facilities to determine if Campylobacter jejuni could be isolated from the raw product or from further-processed egg products intended for human consumption. No C. jejuni were detected in any of the egg or egg-product samples or from water samples collected from the overflow of the egg washer. Campylobacter jejuni was recovered from all control samples, which had been inoculated at the plants. These findings suggest that properly processed egg products are an extremely unlikely source of C. jejuni contamination.