Influence of increasing breast meat yield on muscle histology and meat quality in the chicken

The histological characteristics, ie, myofibre types and cross-sectional areas (CSA), of pectoralis major and sartorius muscles of 20 male chickens from two lines (ten birds from each line) divergently selected for breast meat yield were compared. Moreover, some quality parameters (ie, drip loss, ultimate pH value and meat colour) of the breast muscle were recorded. The animals from both lines displayed identical pectoralis major myofibre types and CSA. A slight difference in typology, but not in myofibre CSA, was observed in the sartorius muscle: animals with the highest breast meat yield tended to have a more pronounced glycolytic character. No significant difference was observed in the quality of breast meat (pH, colour and drip loss).     

Immune and physiological responses of turkeys with green-liver osteomyelitis complex

A study of field turkeys was undertaken in order to determine the involvement of relative immunological differences in the etiology of turkey osteomyelitis complex (TOC). Lame and normal turkeys were sampled from commercial flocks just prior to processing in two separate trials. After testing for functions of both humoral and cellular immunity, the turkeys were necropsied and examined for lesions of TOC. There were significantly higher relative spleen and over weights and significantly lower body weights and relative bursal weights in birds with TOC. The birds with TOC had lower response to phytohemagglutinin-P in both in vivo and in vitro tests as well as lower circulating lymphocyte counts and higher monocyte, heterophil, and total white blood cell counts. There was a significantly higher antibody response to sheep red blood cells in turkeys with TOC, whereas antibody response to Salmonella pullorum antigen was not different. There were no significant differences in the percentages of mononuclear cells or heterophils able to phagocytize bacteria or latex particles, or kill bacteria; however, the heterophils from turkeys with TOC lesions did phagocytize significantly fewer latex particles per cell than did those of the healthy turkeys. Total serum protein, uric acid, and blood urea nitrogen levels were higher in birds with TOC, whereas hemoglobin, iron, alkaline phosphatase, and gamma-glutamyl-transferase levels were lower. Although many of the differences in birds with TOC could be caused by the normal host reaction to infection, further study may reveal innate differences that contribute to susceptibility to TOC.     

Inhibition of pink color development in cooked, uncured ground turkey through the binding of non-pink generating ligands to muscle pigments

The pink color defect in cooked, uncured turkey is a sporadic problem that can result in economic loss and consumer dissatisfaction. Fourteen ligands were tested in ground turkey samples for their ability to reduce pink color development in control samples and in the presence of 150 ppm sodium nitrite or 1.0% nicotinamide (pink color producing agents). The 14 ligands evaluated were: 3-amino pyridine (AP), 4-benzoylpyridine (BP), diethylenetriamine pentaacetic acid (DA), ethylenedinitrilo-tetraacetic acid disodium salt (EA), 2,3 dihydroxybenzoic acid (DB), 3-ethyl pyridine (EP), trans 1,2-diaminocyclohexane-N,N,N',N' tetraacetic acid monohydrate (HA), calcium reduced nonfat dried milk (NM), 2,3 phthalic acid (PA), 3-picoline (PC), pyrrole (PY), pyridazine (PZ), pyridinedicarboxcylic acid (YA), and pyrazinedicarboxcylic acid (ZA). All ligands were incorporated into ground turkey at 0.20 mg/g (meat weight basis) except for NM (30 mg/g). Color was evaluated using a reflectance spectrophotometer to measure pigment changes (nicotinamide hemochrome, nitrosohemochrome) and with a chroma meter to determine CIE L* a* b* values. Reduction in pink color development was apparent with the addition of the ligand alone and in the presence of sodium nitrite and especially nicotinamide. The four most effective ligands tested were DA, EA, HA, and NM. In general, pink color reduction was highest in the ligand only and the ligand plus nicotinamide samples as was observed by CIE a* and nicotinamide hemochrome value reductions.     

Effects of amino acid restriction during starter and grower periods on subsequent performance and incidence of leg disorders in two strains of male large white turkeys

Male turkeys of two commercial Large White strains (Nicholas 88, BUT 6) were subjected to growth restriction by means of reducing amino acid (AA) content of diets to a minimum of 75% of NRC (1994) suggested levels. There were three periods when diets containing 75% of NRC recommended AA for that age period were fed ad libitum: 0 to 3 wk, 0 to 6 wk, or 6 to 12 wk. A fourth (control) group was not restricted in AA content at any time. When turkeys were not fed the AA-restricted diets they were fed diets formulated to meet a minimum of 100, 110, or 120% of NRC (1994) AA recommendations, which resulted in a 3 x 4 factorial arrangement of treatments with three AA levels by four restriction times. Four pens of 12 males each were fed each AA by restriction time combination. At 18 wk, all birds were scored individually for leg condition and representative samples of turkeys were processed for parts yield. Birds fed restricted diets from 0 to 6 or 6 to 12 wk had significantly lower BW at 18 wk than control birds. Birds fed the restricted diets from 0 to 3 wk did not differ significantly in 18-wk BW compared to control birds but the magnitude of difference was similar to that observed at the end of the restriction period. Feed utilization was not improved by early AA restriction. Restricting early growth resulted in a significantly higher incidence of birds with no leg disorders and a lower incidence of birds with moderate leg disorders than control birds. Feeding higher AA levels during realimentation resulted in a greater severity of leg disorders. Breast meat yield was depressed significantly as severity of early restriction increased. Increasing dietary AA above NRC (1994) recommended levels generally improved performance during realimentation but was not able to compensate for reduced gains during restriction.     

Indocyanine-green videoangiography of drusen as a possible predictive indicator of exudative maculopathy

OBJECTIVE: Recent studies have shown that indocyanine-green videoangiography (ICG-V) is useful to image occult choroidal neovascularization. The authors studied the ICG-V findings in fellow drusen eyes of patients with unilateral exudative age-related macular degeneration (AMD). The authors also studied the occurrence of exudative changes to determine whether ICG-V is useful in predicting future exudative changes in these eyes with only drusen. DESIGN: Cohort study. PARTICIPANTS: The authors studied 432 consecutive patients diagnosed with unilateral exudative AMD in whom the fellow eye had only drusen by clinical fundus examination and fluorescein angiography. All of these eyes had ICG-V performed. Follow-up data were obtained in all eyes with abnormal indocyanine-green (ICG) angiograms and randomly sampled ICG angiograms of normal eyes. MAIN OUTCOME MEASURES: The initial ICG findings were classified as showing normal or abnormal hyperfluorescence. Abnormal hyperfluorescence eyes were subdivided into focal spots (focal areas of hyperfluorescence < 1 disc area in size) and plaques (areas of hyperfluorescence > 1 disc area). The development of exudative changes in eyes with normal and abnormal hyperfluorescence was compared. RESULTS: Of the 432 fellow eyes, 386 (89%) eyes with drusen had a normal ICG-V study, whereas 46 (10 focal spots and 36 plaques) (11%) eyes had an abnormal ICG-V. Exudative changes occurred in 6 (10%) of 58 normal ICG eyes and 9 (24%) of 38 eyes with abnormal ICG findings during a mean follow-up period of 21.7 months. The difference between drusen eyes with normal ICG angiograms and those with plaques on ICG-V regarding future exudative changes (10% vs. 27%, respectively) was statistically significant (P = 0.038). CONCLUSIONS: Abnormal ICG findings were found in 11% of eyes with clinically and fluorescein angiographically nonsuspicious drusen. The subgroup of patients with plaques on ICG-V had a higher chance of having exudative changes develop. Indocyanine-green videoangiography may be a predictive indicator of future exudative changes in eyes with drusen. A much larger prospective study seems justified.     

Further studies on the influence of genotype and dietary protein on the performance of broilers

An experiment was conducted to quantify genetic differences in response to dietary protein level of male vs female broilers. Broilers (1 d old) from a "high-yield" strain cross (Ross x Ross 208) and a "fast-growing" strain cross (Peterson x Arbor Acres) were placed on fresh pine shavings in floor pens. From Day 0 to 18, all birds were fed a 23% CP starter diet. During Days 18 to 53 male birds were fed either a 16, 18, 20, 22, 24, or 26% CP diet (3,200 kcal ME/kg) and female birds were fed the 16, 20, or 24% CP diet. Significant differences (P < 0.05) were noted in the performance of the different strains. Ross x Ross 208 male birds had a higher body weight (3.37 vs 3.16 kg), higher feed intake (7.08 vs 6.78 kg), higher breast yield (31.76 vs 29.25%), higher carcass yield (73.90 vs 71.85%), and a lower adjusted feed conversion ratio (FCR; 2.10 vs 2.16 g:g) than Peterson x Arbor Acres males at 53 d of age. As compared to Peterson x Arbor Acres females, Ross x Ross 208 female broilers also had a higher body weight (2.68 vs 2.55 kg), higher breast meat yield (33.61 vs 30.80%), higher carcass yield (75.31 vs 73.91%), and lower adjusted FCR (1.97 vs 2.04 g:g). Qualitative differences in the response of these strains were confirmed and better qualitative data is presented that can be used to predict the important output parameters from the import inputs in broiler production.     

Prevalence and demographic determinants of metronidazole resistance by Helicobacter pylori in a large cosmopolitan cohort of Australian dyspeptic patients

1. Heterozygous naked neck birds were raised under natural spring (average 21.2 degrees C) and summer temperatures (average 27.1 degrees C) to investigate the influence of dietary energy on broiler performance, carcase yield and nutrient composition of breast meat. 2. Birds were fed on a low energy diet of 12.12 MJ ME/kg, a medium energy diet of 12.96 MJ ME/kg and a high energy diet of 13.79 MJ ME/kg with 2 protein concentrations per energy treatment, 230 and 200 g/kg, from 0 to 3 and 3 to 7 weeks of age, respectively. 3. Summer rearing resulted in a decrease in body weight, body weight gain, carcase weight and carcase part yields of birds. 4. Increasing dietary energy from 12.12 to 13.79 MJ ME/kg increased body weight at 3 and 7 weeks, body weight gains from 0 to 3 and 3 to 7 weeks, carcase weights and relative abdominal fat weights of birds in a linear manner. There was no effect of dietary energy on the nutrient composition of breast meat. 5. It was concluded that there was no differences in dietary energy requirements of heterozygous naked neck birds when grown under natural optimum (21.2 degrees C) and summer temperatures (27.1 degrees C).     

Welfare during stunning and slaughter of poultry

This paper describes research on the electrical stunning of poultry and the problems of achieving an effective humane stun with water bath stunners. The welfare and meat quality advantages of using gas mixtures to stun and kill birds are then described. The evidence strongly suggests that chickens and turkeys can be killed very humanely using either 90% argon in air or a mixture of 30% carbon dioxide and 60% argon in air.     

Protection of turkeys against haemorrhagic enteritis by monoclonal antibody and hexon immunization

Virus-neutralizing monoclonal antibodies specific for the hexon of haemorrhagic enteritis virus (HEV), a turkey adenovirus, were examined for their ability to confer passive protection against haemorrhagic enteritis (HE) in turkeys. A high dose of antibody prevented clinical disease and reduced virus replication in experimentally infected birds. This suggests that virus neutralization might be an important mechanism for protection against HE. Subsequently, the use of the hexon protein as a subunit vaccine was investigated by immunizing birds with affinity-purified HEV hexon. The birds were tested for the appearance of hexon-specific antibodies in their sera, for protection from clinical disease, and prevention of virus replication after challenge with virulent HEV (HEV-V). Regardless of whether birds were immunized with native or denatured hexon, high ELISA antibody titres were produced to each immunogen. A virus-neutralizing antibody response was induced by immunization with the native hexon but not by immunization with the denatured protein. All turkeys twice immunized with a dose of at least 1 microgram, and four out of five birds immunized with two doses of 0.3 micrograms of purified native hexon, were protected against virus-induced disease and virus replication. In contrast, birds inoculated with denatured hexon were not protected. These results demonstrate the importance of the native (trimeric) structure of the hexon protein for eliciting a protective immune response. The impact of these results on the development of a vaccine for HE in turkeys produced by recombinant DNA technology is discussed.     

The role of hyperthermia in the water economy of desert birds

A number of authors have suggested that hyperthermia, the elevation of body temperature (Tb) 2 degrees-4 degrees C above normal, contributes to a reduction in total evaporative water loss (TEWL) in birds. Information about the role of hyperthermia in the water economy of birds is scattered throughout the literature. We purposed to collate the available information on this subject, to reevaluate the benefits and costs of this process, and to assess its net effect on the water economy of birds, especially species living in deserts. In this review, we first consider the current model of heat balance in birds at high ambient temperatures (Ta), and show that, in most studies performed at a high Ta, birds were increasing their Tb, a violation of the assumption of steady state conditions. Next, we incorporate the rate of heat gain into calculations of the dry heat transfer coefficient (h), below and above temperature equality (Ta=Tb). We develop a method to calculate h at Ta=Tb, using l'H?pital's rule. The combined result of our approach suggests that birds increase their dry heat transfer even when Ta is above Ta=Tb, contrary to our prediction. Finally, we explore aspects of hyperthermia that reduce water loss, such as an improved thermal gradient and heat storage, and aspects that may augment water loss, the latter a result of increased respiratory water loss when Tb is elevated. Our analysis of the combination of these three factors suggests that, during acute exposure to high Ta (1 h), birds over a size range of 10-1,000 g save about 50% of their TEWL by becoming hyperthermic. For chronic episodes of high Ta (5 h), small birds save water by hyperthermia but large birds do not.     

Ornithine decarboxylase activity in muscle, liver, and intestinal tissue of turkeys during a short-term feed withdrawal and following refeeding

The activity of ornithine decarboxylase (ODC), an enzyme associated with cellular growth and protein synthesis, was examined in breast muscle, liver, and intestinal tissues of turkeys during a short-term period of feed withdrawal (FW) and following refeeding. Turkeys from a randombred control line were reared under standard management practices to 3 wk of age in battery brooders. Feed was then withdrawn from FW birds for a 48-h period, after which feed was consumed ad libitum. Control birds consumed feed ad libitum throughout the test period. Tissues were collected from 12 birds per treatment following 24 and 48 h of FW and at 6, 12, 24, and 48 h following refeeding for later determination of tissue ODC activity. Activity of ODC was greater in tissue from the small intestine than in liver tissue and both had greater activity than that exhibited by breast muscle. Short-term FW and refeeding produced differential responses in ODC activity of the three tissues examined. Feed withdrawal resulted in a reduction of ODC activity in intestinal tissue, whereas activity was unaffected for liver or breast muscle tissues. Compensatory increases in ODC activity were observed in liver and intestinal tissues; however, the increase was both more rapid and transitory in small intestine than in liver tissue. The ODC activity in breast muscle was largely unaffected by short-term FW and refeeding. Patterns of ODC activity in liver during FW and refeeding closely resembled patterns observed for absolute and relative liver weight. Thus, the results of the present experiment demonstrate that short-term FW and refeeding influence underlying growth mechanisms of supply organs, such as hepatic and intestinal tissue, in addition to affecting overall growth and muscle development.     

The relationships between p53-dependent apoptosis, inhibition of proliferation, and 5-fluorouracil-induced histopathology in murine intestinal epithelia

The relationship between acute (<36 h) induction of apoptosis and longer-term (>72 h) intestinal histopathology was systematically investigated in vivo using p53 wild-type (+/+) and null (-/-) mice. Administration of the enterotoxin 5-fluorouracil (5-FU) at either 40 or 400 mg/kg to BDF1 mice induced an acute p53-dependent apoptosis in the crypts of both small intestine and midcolon. Although the amount of apoptosis was of the same order of magnitude at its peak (24 h) at both doses, only 400 mg/kg 5-FU brought about histopathological changes to the gut after 96 h, quantified as losses of crypt and villus cellularity. Only after the administration of 400 mg/kg 5-FU were mitotic index and DNA synthesis significantly suppressed in both small intestinal and midcolonic crypts at 24 h. This correlated with a prolonged, p53-dependent expression of p21waf-1/cip1. In p53 null (-/-) mice, significant reductions in both 5-FU-induced apoptosis and inhibition of cell cycle progression allowed retention of crypt integrity 96 h after 5-FU. These results show that quantitative measures of acute apoptosis in vivo may not accurately predict subsequent pathological changes in the gut. Rather, p53-dependent inhibition of cell cycle progression, together with cell loss by apoptosis, caused a loss of crypt integrity. Importantly, the tissue toxicity of 5-FU was genetically determined at a locus (p53) separate from that directly associated with drug action.     

Relationship between long bone distortion and tibial dyschondroplasia in male turkeys

To determine whether a relationship exists between long bone distortion and tibial dyschondroplasia (TD), the hock joints of Large White commercial male turkeys were examined using low intensity x-ray imaging (hand-held lixiscope). All lame birds with long bone distortion and 96 control birds without lameness were examined at 8.3 and 12.3 wk of age for TD lesions using a lixiscope. Results indicated that the incidence of TD was less than 2% at 8.3 wk of age. The incidence increased to 21% by 12.3 wk of age. The TD lesions at 12 wk of age were considered mild covering only one-fourth of the growth plate. Chi-square analysis indicated that control turkeys without long bone distortion were just as likely to have TD lesions as were lame turkeys with long bone distortion. Under the conditions of the present experiment, TD did not appear to be a significant skeletal problem in Large White commercial male turkeys prior to 12.3 wk of age. Only 5 out of 37 (14%) toms with long bone distortion at 12.3 wk of age had TD lesions, suggesting that the valgus-varus deformity may be independent of TD.     

Relationships of meat characteristics of two lines of rabbits selected for litter size and growth rate

We measured meat characteristics of 46 commercial rabbit carcasses from two synthetic breeds selected for litter size or growth rate. Color measurements (CIELAB) were made on several muscle surfaces. Color measured on the muscular aponeurosis indicated a pale carcass at most of the points; Chroma (C*) and hue (H*) varied from 3.71 and 31.1, respectively, for longissimus at the 7th lumbar vertebra to 14.3 for C* of trapezius and 56.1 for H* of biceps femoris. Color of the longissimus cut surfaces differed substantially from the exterior surface color. The 1st lumbar vertebra cut also differed from the 7th lumbar vertebra cut. The pH of the biceps femoris was 5.80 and that of the longissimus was 5.75. Meat fat content of half a carcass was 5.28%. The first four principal components of an analysis with color and pH measurements of the longissimus and biceps femoris and meat fat content explained 68% of the variance. The entire set of variables was well summarized by the lightness (L*) and Chroma of the longissimus muscle exterior surface measured at the 4th lumbar vertebra, longissimus pH, and meat fat content. When the data were projected on the plane defined by the first two principal components, two separate groups of points appeared, corresponding to the animals of each breed.     

Lack of protection against avian cholera by vaccination with recombinant P6-like protein from Pasteurella multocida

The gene encoding the P6-like protein of Pasteurella multocida was cloned in the baculovirus expression system. Baculovirus-expressed recombinant protein was used to parenterally immunize 6-wk-old Nicholas broad-breasted white turkeys. Turkeys developed significant antibody titers to the recombinant protein as measured by enzyme-linked immunosorbent assay. Two weeks after the last immunizing injection, vaccinated turkeys were placed in contact with turkeys infected with P. multocida strain P1059, as were nonvaccinated control birds. No differences occurred in percent mortality between the two groups. We conclude that parenterally administered recombinant P6-like protein does not protect turkeys from avian cholera.     

Mycoplasmas in wild turkeys living in association with domestic fowl

One hundred and nineteen Merriam's wild turkeys (Meleagris gallopavo merriami) and 31 domestic chickens coexisting on a ranch in west-central Colorado (USA) were surveyed for mycoplasmosis by serologic and cultural methods. Although no clinical signs were apparent in any wild turkeys tested, 51 (43%) had positive rapid plate agglutination (RPA) reactions for M. gallisepticum (MG) and/or M. synoviae (MS); 37% of 56 adults and 48% of 63 subadults were classified as positive reactors to MG and/or MS. No turkeys tested in 1992 (n = 61) and 17 (29%) of 58 turkeys tested in 1993 were RPA-positive for M. meleagridis (MM). Hemagglutination inhibition (HI) test results were negative for MG, MS and MM as were most enzyme-linked immunosorbent assay (ELISA) test reactions (MG = 99%, MS = 93%, MM = 87%). Immunoblotting showed mild to moderate reactivity to MG proteins in 49% of 41 samples tested. Most chickens were strongly positive for MS by RPA (81%), HI (58%) and ELISA (87%); 48% also were positive for MG by RPA but all were MG-negative by HI and ELISA. No pathogenic mycoplasmas were isolated from either group of birds. Mycoplasma gallopavonis was commonly identified from the wild turkeys, and M. gallinaceum was isolated from both the chickens and wild turkeys. In a transmission study conducted in 1994, disease-free domestic turkeys failed to seroconvert when co-housed with wild turkeys from this population that were RPA-positive for MG. Collectively, the results of this study were inconclusive regarding the status of pathogenic mycoplasmas within this wild turkey population.     

Metabolic responses of White Pekin ducks to ambient temperature

Metabolic responses of unrestrained White Pekin ducks, Anas platyrhynchos, were determined at ambient temperatures of -5 degrees, 1 degrees, 10 degrees, 20 degrees, and 30 degrees C. Temperatures from the pectoralis and the subcutaneous back were monitored. Unrestrained ducks exhibited two metabolic states, a high response (540 cc. O2/kg/hr. at 20 degrees C.) and a low response (427 cc. O2/kg./hr. at 20 degrees C). Pectoralis muscle temperature did not vary greatly over the range of ambient temperatures tested and was considered to be a good representative of body temperature.     

Ethnic stratification in northwest China: occupational differences between Han Chinese and national minorities in Xinjiang, 1982-1990

Skin color of free flaps can represent their vascular conditions after reconstructive surgery. Thus far, however, surgeons have subjectively inspected flap color changes. More precise and objective measurement is necessary for early detection of vascular insufficiency. In order to evaluate color changes of flaps we used a portable non-contact type colorimeter with a L*a*b* color space (L* is brightness and a*, b* are chromaticness) recommended by the CIE (Commission Internationale d'Eclairage). Initially, we successfully performed objective evaluation of flap color changes in rats with or without a tied femoral artery or vein. Vein failure showed a decrease in a* and b* soon after surgery, while the artery failure appeared as b* and L* after 12 and 24 hours, respectively. Then, the color differences between sites of clinical free flaps were examined and considered to be relatively negligible against the time-dependent changes using delta a*, delta b*, delta L*, which represents the difference in color of an objective point from a control point. Next, we demonstrated that the color of abdominal skin did not significantly differ from that of forearm skin using delta a*, delta b*, delta L*. The clinical free flaps were measured with these parameters pre- and post-operatively and their normal course of color changes was revealed. The findings showed that a* changed with characteristic ups and downs before and after elevation due to congestion.     

Migraine and other causes of headache

Direct comparisons were made of chlamydial isolation rates from pharyngeal swabs, fecal samples, and cloacal swabs from cockatiels and pharyngeal and cloacal swabs from turkeys experimentally infected with Chlamydia psittaci. During pathogenesis studies, 133 paired specimens were collected from cockatiels and 118 paired specimens were collected from turkeys. Of the 51 cockatiel chlamydial infections detected, 80.4% were positive by the pharyngeal swab sample, 45.1% were positive by the fecal swab sample, and 37.3% were positive by the cloacal swab sample. Of the 87 turkey infections detected, 93.1% were positive by the pharyngeal swab sample and 77.0% were positive by the cloacal swab. The pharyngeal swabs were the most reliable sample for isolation of chlamydia from live birds. However, no single sampling site yielded positive results from all infected birds. Specimens from multiple sites are recommended because a number of infected birds were identified by isolation from only 1 sample.     

Excessive mortality in market-age turkeys associated with cellulitis

Between July, 1993, and October, 1994, seven cases were examined that consisted of increased mortality in commercial turkeys due to cellulitis. The condition started at 13-16 wk of age in toms and persisted until the birds were marketed. The mortality rate was 1-2% per week. Lesions began on the ventrum of the tail and consisted of swelling and the formation of vesiclelike structures. Most of the affected birds also had an accumulation of gelatinous fluid in the subcutis of the tail and breast areas. The underlying musculature was often darkened or petechiated. Clostridium perfringens type A was isolated from two of the cases. Lesions similar to those found in the field were reproduced experimentally in turkeys injected with the subcutaneous fluid obtained from birds in field cases.