Effects of in ovo injection of L-carnitine on subsequent broiler chick tissue nutrient profiles.

Effects of in ovo injection of L-carnitine on BW and the moisture and nutrient biochemical concentrations of various organs and muscles of Ross x Ross 308 broiler chicks, hatched from eggs laid by a 28-wk-old breeder flock, were determined through 48 d posthatch. Eggs containing live embryos were injected in the amnion with L-carnitine (0.5, 2.0, or 8.0 mg dissolved in 100 microL of a commercial diluent) on d 18 of incubation using an automated egg injector. Three control groups (noninjected and injected with or without diluent) were also included. On d 0, 3, 10, 28, and 48 posthatch, bird BW and the proportional weights and moisture concentrations of various organs and muscles were determined. Glycogen, glucose, protein, and fat concentrations were also determined in certain tissue samples. Bird BW; proportional liver weight; breast, thigh, and gastrocnemius muscle moisture; liver glycogen, glucose, and protein concentrations; and breast and thigh muscle fat and protein concentrations changed with posthatch bird age. Liver glucose on d 0 and pipping muscle moisture on d 3 posthatch were significantly affected by treatment. In comparison to eggs injected with commercial diluent with no added L-carnitine, liver glucose was reduced by the injection of diluent containing either 0.5 or 8.0 mg of L-carnitine, and pipping muscle moisture was increased by the injection of commercial diluent containing either 0.5 or 2.0 mg of L-carnitine. The modified concentrations of the 2 parameters in response to these treatments were not different from those in noninjected control eggs. In conclusion, L-carnitine added to commercial vaccine diluent at levels between 0.5 and 8.0 mg/100 microL for the commercial injection of broiler hatching eggs may decrease liver glucose and increase pipping muscle moisture concentrations of chicks on d 0 and 3 posthatch, respectively, so that their levels are commensurate with noninjected controls.

Pipping muscle and liver metabolic profile changes and relationships in broiler embryos on days 15 and 19 of incubation.

The relative proportions and relationships of pipping muscle and liver nutrients in broiler embryos on d 15 and 19 of incubation were determined. Ninety hatching eggs obtained from a 30-wk-old broiler breeder flock were incubated on 3 replicate tray levels (30 eggs per tray) for 19 d. On 15 and 19 d of incubation, 10 live embryos per tray level were necropsied to collect pipping muscle and liver samples. As the broiler embryo developed between d 15 and 19 of incubation, the glycogen and protein concentrations of the pipping muscle increased, whereas those of the liver decreased, and the fat concentration of the pipping muscle decreased, whereas that of the liver increased. Across d 15 and 19, pipping muscle glycogen was negatively correlated with liver fat, whereas on d 15, pipping muscle glucose was negatively correlated with liver fat, and pipping muscle glycogen was negatively correlated with liver glucose and glycogen. Pipping muscle fat was negatively correlated with liver glucose on d 15 but positively correlated with liver glycogen on d 19. In conclusion, in preparation for hatch between d 15 and 19 of incubation, weights of the liver and pipping muscle of broiler embryos increased relative to their BW. This occurred in association with the accumulation of glucose, glycogen, and protein and with the loss of fat in the pipping muscle. The carbohydrate stores in the pipping muscle were supported by the active metabolism of the liver before 19 d of incubation, which included the transfer of glucose and fatty acids to the pipping muscle via the circulation. Despite the liver's active supply of these nutrient subunits for assimilation and oxidation by the pipping muscle, there was an overall accumulation of hepatic fat between d 15 and 19 of incubation. These data suggest that the integrated changes in the energy profiles of pipping muscle and liver between 15 and 19 d of embryogenesis are integral to the broiler embryo's preparation for hatch.

Methodologies of tissue preservation and analysis of the glycogen content of the broiler chick liver.

The current study was performed to develop convenient, rapid, reliable, and pragmatic methodologies by which to harvest and preserve liver tissue glycogen and to analyze its levels within reasonable limits of quantification and with extended chromophore stability. Absorbance values decreased by 2 h and again by 24 h after preparation of the iodine-potassium iodide chromophore, whereas absorbance values of the phenol-sulfuric acid chromophore remained constant over the same time period. These absorbance trends for each chromophore followed full color development within 5 min after combining the analyte with the respective chromophore reagent. Use of the phenol-sulfuric acid reagent allowed for a 10-fold reduction in assay limits of detection and quantification when compared with the iodine-potassium iodide reagent. Furthermore, glycogen concentration-absorbance relationships were affected by the source (i.e., rabbit liver vs. bovine liver) of glycogen standards when the iodine-potassium iodide chromophore was used, but the source of the standards had no influence when the phenol-sulfuric acid chromophore was used. The indifference of the phenol-sulfuric acid method to the glycogen source, as exhibited by similar linear regressions of absorbance, may be attributed to actual determination of glucose subunit concentrations after complete glycogen hydrolysis by sulfuric acid. This is in contrast to the actual measurement of whole glycogen, which may exhibit source- or time-related molecular structural differences. The iodine-potassium iodide methodology is a test of whole glycogen concentrations; therefore, it may be influenced by glycogen structural differences. Liver tissue sample weight (between 0.16 and 0.36 g) and processing, which included mincing, immediate freezing, or refrigeration in 10% perchloric acid for 1 wk prior to tissue grinding, had no effect on glycogen concentrations that were analyzed by using the phenol-sulfuric acid reagent. These results indicate that small field samples may be minced, immediately placed in 10% perchloric acid without freezing, and then processed in the laboratory up to 1 wk later when using a phenol-sulfuric acid reagent, as described in this study, to determine the glycogen concentration in broiler chick livers accurately.

Effects of injected gluconeogenic supplementation on the performance of broilers from young breeders.

Previous research has shown that administering carbohydrates to late-term embryos increases chick hatching weight and liver glycogen content and that supplementing broiler chicks from young hens at day of hatch with subcutaneously injected hydrolyzed casein and thiamine enhances their early performance. It was hypothesized that other practical and readily available gluconeogenic energy sources, including hydrolyzed casein, may similarly be given to hatchlings from immature breeder hens to increase the availability of liver glycogen reserves and augment growth. In addition to physiological saline (sham) and hydrolyzed casein treatments, 2 other treatments containing practical gluconeogenic energy sources (chicken egg crude albumin or albumin hydrolysate) were tested in the current study using hatchlings that were subsequently provided adequate brooding and nutrition. Added biotin was included in the crude albumin treatment. There were no treatment effects on mortality, BW gain, feed or water consumption, feed conversion, body temperature, hematocrit, plasma refractive index, relative liver weight, or liver glycogen content at any of the ages or age intervals examined through d 16 posthatch. These results suggest that under proper brooding conditions and timely feed provision, growth is not facilitated by injected casein hydrolysate, chicken egg crude albumin, or chicken egg albumin hydrolysate during the early transition from fat to carbohydrate-based nutrient uptake in posthatch chicks from young breeder hens.

Relationships among prehatch and posthatch physiological parameters in early nutrient restricted broilers hatched from eggs laid by young breeder hens.

The objective of this study was to establish relationships among various physiological parameters in early (through 72 h posthatch) nutrient restricted broiler chicks from young breeder hens. Despite a 19% decrease in mean BW between 0 and 72 h posthatch, there were no chick mortalities. Liver glycogen peaked at 24 h, and peaks in rectal temperature, plasma glucose, and plasma refractive index occurred at 48 h. By 24 h, negative correlations were noted between BW and relative liver weight and between liver glycogen and both refractive index and rectal temperature. By 24 h, positive correlations were noted between relative liver weight and liver glycogen, BW and plasma glucose, rectal temperature and plasma glucose, and rectal temperature and body fat loss score. Mean daily relative egg weight loss between 0 and 19 d of incubation (RIEWL) was positively correlated with rectal temperature at 0 h but was negatively correlated with rectal temperature at 24 h and liver glycogen at 24 and 48 h. Furthermore, mean relative hatching chick weight (RHCW) had significantly positive correlations with plasma glucose at 6 h and rectal temperature at 48 and 72 h. Broilers having a greater RHCW after hatching from eggs with a lower RIEWL may maintain higher metabolic rates between 24 and 72 h posthatch despite nutrient deprivation. However, broiler chicks from eggs exhibiting a higher than optimal RIEWL may have greater dependence on gluconeogenesis, thus requiring stricter management during initial brooding.

Chemiluminescent detection of infectious bursal disease virus with a PCR-generated nonradiolabeled probe.

A polymerase chain reaction (PCR)-generated digoxigenin-labeled nonradioactive oligonucleotide probe was developed and utilized in slot-blot hybridization coupled with chemiluminescence for the detection of infectious bursal disease virus (IBDV). The probe was prepared from the RNA of the standard challenge strain (STC) of IBDV serotype 1 by reverse transcription followed by 2 PCR amplifications with 2 separate sets of primers. RNA of STC viruses prepared from bursae infected with STC viruses was subjected to the first PCR with the outer primers V8 and V9 that amplified a 607-base pair (bp) segment. The PCR product from the first PCR was eluted following agarose gel electrophoresis and subjected to the second PCR with the nested primers V6 and V7 that flanked a 351-bp segment. In the second PCR, dTTP was substituted by digoxigenin-11-dUTP in the PCR reaction mixture so that the amplified 351-bp DNA products were labeled with digoxigenin. The specificity of the PCR-generated digoxigenin-labeled probe was tested on different strains of IBDV, several unrelated avian viruses, and bacteria by slot-blot hybridization assay. Hybridization was detected by chemiluminescence. The sensitivity of the probe was assayed using 10-fold serial dilutions of purified RNA from the STC strain of IBDV. The PCR-generated digoxigenin-labeled probe hybridized with genomic RNA of STC and variant strains A, D, E, G, and GLS-5 of IBDV serotype 1 but not OH strain of IBDV serotype 2. The probe did not react with avian reovirus, infectious bronchitis virus, Salmonella enteritidis, Escherichia coli, or Staphylococcus aureus.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic relationships of infectious bronchitis virus isolates from Mississippi broilers.

A 582-base pair segment located in the nucleocapsid protein terminal part of the S1 gene of 26 Arkansas (Ark)-type infectious bronchitis virus (IBV) isolates from Mississippi broilers was amplified and sequenced. Reverse transcription-polymerase chain reaction and cycle sequencing techniques were used to elucidate the genetic and deduced amino acid relationships among the isolates. Analysis suggested that the nucleotide and amino acid sequences of the isolates were highly conserved, with greater than 99.4% nucleotide and 98.4% amino acid homology among the Mississippi isolates. The Mississippi isolates had less than 2.3% nucleotide and 5.2% amino acid variation when compared with the vaccine strain Ark DPI and less than 3.0% nucleotide and 5.2% amino acid variation when compared with the Ark-type Georgia variant. This study suggests that the 26 IBV isolates that are genetically closely related to the vaccine strain may be derived from the vaccine strain by point mutation. The results also indicate that within a 1-yr period Ark-type IBV in Mississippi was spread with little or no change in its genetic sequence. The 21 identical isolates appeared in different farms and companies, suggesting that poor biosecurity was practiced and contributed to the spreading of the disease.

Comparison of the immunofluorescent assay and reverse transcription-polymerase chain reaction to detect and type infectious bronchitis virus.

Indirect fluorescent antibody (IFA) assay and reverse transcription-polymerase chain reaction (RT-PCR) are two current methods commonly used for the detection of infectious bronchitis virus (IBV) and its serotypes. The objectives of this study were to compare the two methods relative to detecting IBV in chicken embryos that were artificially inoculated with Mass41, Ark99, or Mass41/Ark99 in serial embryo passages and in tracheas and cecal tonsils collected from vaccinated commercial flocks with and without respiratory problems. The tissues collected from these birds were used to inoculate chicken embryos. The chorioallantoic membranes collected from the inoculated embryos were examined by the IFA assay, and the allantoic fluids collected from the same embryos were subjected to the RT-PCR. The IFA assay and RT-PCR both were able to detect and type IBV when only one IBV strain was inoculated into embryos, regardless of the number of passages. When embryos were inoculated with Mass41 and Ark99 strains simultaneously, both strains were 100% detected by the RT-PCR. By the IFA assay, 20% of samples were positive for two strains and 80% were positive for the Ark only. Two of eight samples collected from healthy flocks that were vaccinated with Mass/Conn/Ark were positive by the IFA assay, and four of eight were positive by the RT-PCR. Sixteen percent (12/75) of the samples from birds experiencing respiratory problems were positive by the IFA assay and 35% (26/75) were positive by the RT-PCR. Results suggest that the RT-PCR is more sensitive than the IFA assay, especially when more than one strain of IBV is involved, but the IFA assay is rapid and cheaper than the RT-PCR.

Subacute to chronic fowl cholera in a flock of Pharaoh breeder quail.

A total of 1300 birds in flock of breeder Pharaoh quail (Coturinix coturnix) experienced a moderate rate of mortality (13%) during a 7-day period. Clinical signs included depression, ruffled feathers, prostration, lameness, inapetence, diarrhea, and periorbital sinus swelling with mucoid discharge and lameness. Gross lesions observed in dead quail were emaciation, carcass congestion, mild hepatomegaly with green discoloration, congested intestinal mucosa, caseous purulent arthritis-osteomyelitis, and thickened crop mucosal epithelium. Histopathologic examination revealed mild hepatic amyloidosis, proliferative parabronchitis, splenic reticular cell hyperplasia, thymic cortical atrophy, subacute bacterial osteomyelitis, periarthritis, and crop mycosis. Pasteurella multocida was isolated from the joints of these birds and the isolates were serotype 3 x 4. These findings suggest that Pharaoh quail are susceptible to P. multocida and are likely to develop subacute to chronic fowl cholera.

Dose-titration to confirm the level of fenbendazole for control of Raillietina cesticillus in broiler chickens.

A total of 452 broiler chickens, naturally infected with Raillietina cesticillus, were allotted into six treatment groups. One group was fed unmedicated broiler ration (Group 1), and the other five groups were fed broiler ration containing fenbendazole at 180 ppm for 3 days (38.5 mg/kg body weight [BW]), 240 ppm for 3 days (50.9 mg/kg BW), 120 ppm for 6 days (52.2 mg/kg BW), 180 ppm for 6 days (79.9 mg/kg BW), or 240 ppm for 6 days (104.3 mg/kg BW). Fenbendazole was 100.0% efficacious against R. cesticillus when administered in the diet at 240 ppm for 6 days; 99.9% at 240 ppm for 3 days and at 180 ppm for 6 days; 99.5% at 120 ppm for 6 days; and 96.9% at 180 ppm for 3 days. Fenbendazole treatment had no adverse effect on weight gain or feed intake.

A comparison of Eimeria oocysts isolated from litter and fecal samples from broiler houses at two farms with different management schemes during one growout.

Eimeria oocyst populations were monitored in broiler houses on two farms during a growout and prior to the placement of new chicks on the same litter. Numbers of oocysts in litter were enumerated at Weeks 0, 5, 6, 7, and 9 and in feces at Weeks 5,6, and 7 in broiler houses with different management practices (both farms had identical coccidiostat programs but Farm A had a history of poor performance whereas Farm B had excellent performance records). On Farm A the number of oocysts in litter increased (P < .05) at the time of slaughter (Week 7) and placement of a subsequent flock (Week 9) when compared with Day 0. The number of oocysts in feces on Farm A also increased (P < .05) from Week 5 to 7. On Farm B there were no differences in numbers of oocysts in litter or feces over time. Farm B had (P < .05) lower numbers of oocysts in litter than Farm A at Week 7. The number of oocysts in feces from Farm B were consistently lower (P < .05) than Farm A at Weeks 5, 6, and 7. There were no differences in the species of Eimeria in litter between farms; however, there were differences in the species composition over time. Small (Eimeria mitis) and medium (primarily Eimeria acervulina) oocysts increased significantly over time, whereas the large oocysts (Eimeria tenella and Eimeria brunetti) and Eimeria maxima did not change over time. An increase (P < .05) in large oocysts was observed in fecal samples from Farm A over time.

The effect of added complex carbohydrates or added dietary fiber on necrotic enteritis lesions in broiler chickens.

Two trials utilizing two corn diets and four wheat diets were conducted. In Trial 2, all chicks were crop-infused at 9 d of age with Eimeria acervulina. In both trials, a broth culture of Clostridium perfringens was mixed with the diets for 3 consecutive d. Necrotic enteritis lesion scores were lowest in chickens consuming the corn diet with no C. perfringens and highest in chickens fed the wheat diets with C. perfringens. Chickens consuming a wheat diet with no added complex carbohydrates or added fiber exhibited the highest lesion score. Chickens on wheat diets with 4% new, ground, pine shavings had intestinal lesion scores intermediate to those of chickens that consumed the wheat or corn diets. Chickens consuming corn diets yielded the lowest lesion scores. Chickens provided diets containing either guar gum or pectin were not fully consumed and thus probably reduced the number of challenge organisms ingested.