A series of 4 floor pen studies was conducted to evaluate the effects of environmental temperature modification on nicarbazin (NIC) responses in broiler chickens raised to 28 d of age. Birds were reared at either standard temperatures (recommended by the primary breeder for ages zero to 28 d) or at 3°C below this level. From placement to 28 d, birds were provided feeds containing zero, 100, or 125 ppm NIC, comprising a 2 × 3 factorial arrangement in each test. Two of the trials were conducted in the presence of an imposed coccidial challenge and 2 were conducted in healthy animals. At 18 and 28 d of age, performance was recorded; cloacal temperatures were measured at 7, 14, 21, and 26 days. Mortality data were collected daily and coccidial lesions were scored at 6 d post challenge. Results of these studies revealed that NIC improved coccidial lesion scores regardless of environmental temperature. In the absence of coccidial challenge, NIC depressed performance, but reductions in environmental temperature diminished the magnitude of these responses. Under conditions of coccidial challenge, NIC significantly improved body weight gains in both temperature environments. Compared to standard temperature conditions, lower environmental temperatures exerted a positive effect on feed conversion rates of NIC-fed broilers. Birds reared in the low temperature environment exhibited lower cloacal temperatures than standard environment groups throughout the test period. Irrespective of coccidial challenge, lower environmental temperatures significantly reduced nicarbazin mortality compared to standard temperature groups, resulting in a significant nicarbazin x temperature interaction. This finding indicates that temperature modification is a practical method for minimizing mortality over the course of 28-day nicarbazin usage.
Four chick and five poult trials were conducted in order to investigate the anticoccidial efficacy of monensin against Eimeria mitis in chickens and Eimeria dispersa in turkeys. The chicks were fed a basal diet with either 0 or 100 ppm of monensin. The poults were fed a basal diet with either 0 or 60 ppm of monensin. Two days after the initiation of each experiment, the chicks and poults were crop-intubated with oocysts of E. mitis and E. dispersa, respectively. A group was also included that was not infected and not medicated. Growth and feed intake were recorded. At 6 or 7 days postinoculation, the birds were killed by cervical dislocation and were scored for the incidence and severity of intestinal abnormalities. The Eimeria mitis infection reduced (P<.01) gain and the feed:gain ratio, compared with uninfected birds; the E. dispersa infection only reduced (P<.05) gain. Although well-defined, discrete lesions were not observed, marked intestinal abnormalities were noted in birds infected with either E. mitis or E. dispersa. Also, the infected, unmedicated birds had increased (P<.01) intestinal scores compared with uninfected birds or those with infection but treated with monensin. Monensin eliminated the reduction in gain and feed efficiency seen in the infected birds. The infected birds fed monensin had intestinal scores, gain, and feed:gain ratios similar (P>.10) to those for the birds that were not infected and that did not receive medication.
Antimicrobial feed additives classified as growth promoters have been under attack by activist groups opposed to conventional animal agriculture, even though no conclusive scientific evidence has been produced to suggest that their use has adversely affected public health. The purpose of this study was to demonstrate that even today, the use of in-feed antimicrobials has substantial benefits for bird health, and, consequently, for production efficiency, and for the environment. In this experiment, 744 Nicholas female turkeys were fed diets of similar composition and nutrient content with or without virginiamycin (VM) for a total grow-out period of 77 d. The stocking density; feeding and watering equipment; and lighting, ventilating, and feeding programs were similar to those used in commercial turkey production. The target final BW was no less than 14 lb. At the conclusion of the experiment, turkey hens fed the diets supplemented with VM were significantly heavier than those from the control treatment, and on average were 0.294 lb per hen heavier than the control birds. Turkey hens fed the diets supplemented with VM also had significantly better adjusted FCR and had, on average, a 5-point improvement per hen in FCR compared with control birds. The confirmed benefits derived from including 22 ppm of VM in the feed of Nicholas turkey hens raised under commercial conditions were significant (P < 0.05), and when extrapolated to an operation producing 5 million turkey hens per year, would have resulted in an additional 1,474,000 lb of turkey BW and savings of almost 2,000 tons of feed.
A series of studies were conducted to assess the drug sensitivity of 26 coccidial field isolates to the anticoccidial effects of nicarbazin (NIC) and narasin + NIC (NAR + NIC). Isolates were collected from typical broiler farms in the United States from 2003 to 2006, propagated once in the absence of anticoccidial medication, and then used to inoculate broilers that were fed nonmedicated rations or those containing NIC 125 ppm or NAR + NIC 80 ppm. Results of these sensitivity trials indicated that 81% of these coccidial isolates were sensitive to the effects of NIC, but only 22% of these coccidia were controlled by NAR + NIC. Studies conducted to evaluate performance responses to these drugs demonstrated that birds fed NIC gained more weight and utilized feed more efficiently than those receiving NAR + NIC. The results of 2 floor pen tests, conducted to confirm the results of the above sensitivity trials, demonstrated that NIC provided a greater level of protection from coccidiosis than NAR + NIC. Lower lesion scores and improved performance were recorded for birds receiving NIC compared with NAR + NIC. Results of these studies revealed that changes in the susceptibility of Eimeria spp. to the activity of NAR + NIC are evident. These changes appear to be associated with the reduction in ionophore sensitivity that has been documented in most areas of the world.
The stomachs and intestinal tracts of 253 raccoons, Procyon lotor, were examined for hel- minth parasites. Sixteen species of helminths were found including eight trematodes, two cestodes, five nematodes, and one acanthocephalan. Fourteen of these helminths are new geographic records for the state of Tennessee. Multivariate statistical techniques were used to analyze two-state and multistate character sets. Matrices of correlation among characters were computed and the first three principal components were extracted, accounting for 79.7% and 66.5% of the variation in the respective character sets. Three- dimensional projections of Tennessee's eight geographic localities onto two-state and multistate principal components demonstrated that raccoons in western localities were parasitized most heavily by Atriotuenia procyonis, Mesocestoides variabilis, Gnathostoma procyonis, and Pharyngostomoides procyonis. Paral- lelorchis diglossus, Euparyphium beaveri, Eurytrema procyonis, Euryhelmis squamala, Molineus bar- hatus, and Macracanthorhynchus ingens were most common to P. lotor from eastern areas.
Two floor pen trials were conducted to study the effects of 16 anticoccidial programs on broiler performance during a mild coccidial challenge. Twelve shuttle programs were arranged with three starter programs (72 or 90 g/ton narasin + nicarbazin, or 113 g/ton nicarbazin) shuttled to one of four grower programs (100 g/ton monensin, 63 or 72 g/ton narasin, or 60 g/ton salinomycin) at 21 days of age. All feed contained roxarsone and bacitracin MD with the exception of the narasin + nicarbazin feed. Mortality was not affected by anticoccidial programs. All continuous ionophore programs resulted in similar body weights and feed efficiency. During the starter period narasin + nicarbazin and the ionophores provided better gain and feed:gain ratios than nicarbazin. All ionophores provided similar performance during the grower period of the shuttle programs. Birds on the narasin + nicarbazin shuttle programs had greater final weights than birds on either the nicarbazin shuttle or the continuous ionophore programs. These data demonstrate that narasin + nicarbazin to ionophore shuttle programs produce better weight gains than either nicarbazin to ionophore shuttle programs or continuous ionophore programs.
A series of 6 floor pen trials was conducted to determine the effects of a quillaja and yucca combination product on the performance and carcass traits of growing broiler chickens vaccinated for coccidiosis at the hatchery. In each of the trials graded levels (0, 250, and 500 ppm) of a quillaja and yucca combination (QY) were fed to Ross 708 broilers for the duration of each 42 d test. Trials were arranged in completely randomized block designs involving a minimum of 11 blocks per trial. At the start of each trial, pens contained 55 broilers. In order to provide each bird with an enteric disease challenge, 5 kg commercial broiler litter containing 104 CFU Clostridium perfringens per gram was placed in each pen. In addition, the sporulated oocysts of Eimeria acervulina and E. maxima were added to each pen at the outset of each test. At d 21 of the trials, coccidial lesion scores, mortality and performance were determined; final performance and total mortality were assessed at 42 d. At the completion of each test, 10 birds of average body weight per pen were selected for carcass evaluations; whole and chilled carcass yield were determined, and pre- and post-chill breast measurements were made. A combined analysis of the results of the 6 trials (75 replications per treatment) was used to determine treatment effects and each variable was assessed by linear regression analysis. Results indicated that QY significantly reduced mortality and coccidial lesions scores at d 21 (P < 0.05). Performance was significantly improved by both levels of QY at 21 and 42 d, and significant linear effects were observed for these variables (P < 0.05). All carcass characteristics were significantly improved by QY administration and significant linear responses were observed for each carcass variable (P < 0.05). These results indicate that by reducing intestinal disease challenge, QY provided linear improvements in performance. In addition, QY positively affected carcass parameters as each variable responded linearly to QY feeding (P < 0.05).
The purpose of this study was to evaluate the effects of Eimeria acervulina infection (duodenal coccidiosis) on cadmium (Cd) toxicity and zinc (Zn) status in the young chick. Additions of Cd (45 mg/kg) were made to diets that contained either 0 or 52 mg/kg supplemental Zn (from ZnCO3). Duodenal coccidiosis was produced by multiple crop inoculations of 4 × 105 sporulated E. acervulina oocysts. Growth and efficiency of feed utilization were reduced by dietary Cd addition while concurrent coccidial infection reduced these parameters further. Addition of Cd also increased Cd content of liver and kidney and depressed hemoglobin, hematocrit, and plasma Zn content. Coccidial infection exacerbated tissue Cd deposition and depressed hematological parameters further. Although dietary Zn addition ameliorated some of the adverse effects of Cd toxicity, Cd administration tended to enhance tissue Zn deposition. Administration of Cd enhanced synthesis of metallothionein.
The stomachs and intestinal tracts of 253 raccoons, Procyon lotor, were examined for helminth parasites. Sixteen species of helminths were found including eight trematodes, two cestodes, five nematodes, and one acanthocephalan. Fourteen of these helminths are new geographic records for the state of Tennessee. Multivariate statistical techniques were used to analyze two-state and multistate character sets. Matrices of correlation among characters were computed and the first three principal components were extracted, accounting for 79.7% and 66.5% of the variation in the respective character sets. Three-dimensional projections of Tennessee's eight geographic localities onto two-state and multistate principal components demonstrated that raccoons in western localities were parasitized most heavily by Atriotaenia procyonis. Mesocestoides variabilis, Gnathostoma procyonis, and Pharyngostomoides procyonis. Parallelorchis diglossus, Euparyphium beaveri. Eurytrema procyonis, Euryhelmis squamala, Molineus barbatus, and Macracanthorhynchus ingens were most common to P. lotor from eastern areas.
Nicarbazin (NCZ), an effective anticoccidial widely used by the global broiler industry, is known to produce some side effects in broilers. Recent field observations have suggested that NCZ could be associated with spiking mortality syndrome, a disease of uncertain etiology that is most commonly characterized by hypoglycemia. In turn, 2 trials were conducted to investigate the effects of NCZ on the blood glucose levels and liver glycogen content of Ross × Ross 708 male broilers. In 6 of 12 pens beginning at 1 d of age, NCZ was added to basal broiler diets at a rate of 125 mg/kg, and the other 6 pens were control pens in which birds received salinomycin instead of NCZ, at a rate of 66 mg/kg. Feed and water were provided ad libitum, feed was closely monitored in all pens to avoid shortages, no coccidial challenge was imposed, and room temperature never exceeded 29.4°C. At the end of the second trial, a photoperiod increase from 8L:16D to 24L:0D was imposed in an effort to induce stress due to feed engorgement. In response to NCZ in trial 1, 0 to 28 d feed conversion and relative liver weights on d 21 and 28 were higher, whereas 0 to 28 d cumulative BW gain was lower. In response to NCZ in trial 2, 0 to 13 d feed conversion was higher, whereas 0 to 13 d cumulative BW gain was lower. The added NCZ increased blood glucose on d 13 in trial 2, but did not affect at any time the liver constituents analyzed in both trials. In conclusion, the uninterrupted feeding of NCZ at 125 mg/kg in the starter and grower diets of male Ross × Ross 708 broilers increased feed conversion and reduced BW gain, but despite an increase in relative liver weight on d 21 and 28 posthatch, liver glucose and glycogen concentrations were not affected.
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