Welfare assessment of broiler breeders that are food restricted after peak rate of lay.

1. Broiler breeder females were reared on one of three growth curves (ad libitum, conventional or modified restriction) and given rations containing a high or low concentration of crude protein. After the peak rate of lay they were fed ad libitum or a decreasing quantity of food in response to declining egg production. The welfare of the birds was assessed by determining the changes in indices of welfare at 36, 48 and 60 weeks of age. 2. Body weight increased rapidly in restricted birds fed ad libitum post-peak and water intake declined. 3. Post-peak food restriction was associated with a decrease in resting and increased drinking and spot-pecking activities. Birds that were food restricted during rearing spent more time foraging and spot-pecking at 36 and 48 but not 60 weeks of age. 4. Immune function increased with age but was not affected by the experimental treatments. The heterophil-lymphocyte ratio in birds fed ad libitum during rearing was numerically lower at 36 and higher at 48 and 60 weeks of age compared with restricted birds. 5. There was no effect of treatment on plasma corticosterone concentration. Creatine kinase activity was high at 60 weeks in treatments that were characterised by poor reproductive status and the activities of other enzymes reflected differences in reproductive status and mortality. 6. There was no long-term welfare or production advantage from feeding low protein rations or more generous feeding during the rearing period compared with conventional food restriction programmes.

Welfare assessment of modified rearing programmes for broiler breeders.

1. Female broiler breeders were fed ad libitum or a restricted quantity of food to achieve either a recommended body weight curve or a modified (linear) growth curve that allowed more generous feeding between 6 and 15 weeks of age. The birds were fed a ration containing either a normal or low concentration of crude protein. The welfare of the birds was assessed using a profile of indices of welfare at 6, 12, 18 and 24 weeks of age. 2. The low-protein ration decreased the body weight of birds fed ad libitum and restricted birds were fed substantially more of the low-protein ration to meet target body weights from 3 to 14 weeks of age. 3. The modified restricted rearing programme did not have an effect on indices of welfare. 4. Water intakes and plasma corticosterone concentrations were lower in restricted birds fed the low-protein ration and they spent more time resting, and less time spot-pecking, than birds fed the high-protein ration. 5. Birds fed ad libitum on both rations spent more time resting and less time foraging, drinking and spot-pecking than food restricted birds and were more fearful than restricted birds at 6, 12 and 18 weeks of age. 6. The heterophil:lymphocyte ratio in restricted birds was higher at 6 weeks and lower at 24 weeks compared with birds fed ad libitum. Humoral immunity was lower at 6 weeks of age in birds fed ad libitum and was similar at other ages. Cell-mediated immunity was similar among all treatments. 7. Plasma corticosterone concentrations were higher in restricted birds compared with birds fed ad libitum. Plasma creatine kinase activity was higher in birds fed ad libitum at 6, 12 and 18 weeks of age. Alkaline phosphatase and lactate dehydrogenase activity were higher whereas AST was lower in restricted birds compared with those fed ad libitum. 8. There was no evidence to support the use of low protein rations or linear growth curves to improve welfare in restricted broiler breeder females.

Welfare of food restricted male and female turkeys.

1. The welfare of male and female male-line turkeys fed ad libitum or food-restricted was determined at 4, 8, 12, 16, 20, 24, 28, 36(38) and 46(48) weeks of age using behavioural and physiological indices of well-being. Traditional turkeys fed ad libitum were kept as a control treatment. Restricted male and female male-line turkeys were fed to 0-5 during rearing and subsequently to 0-8 of sex-specific ad libitum-fed body weight. In another treatment, male-line males were fed ad libitum to 18 weeks and 0.8 of ad libitum thereafter. 2. Traditional turkeys and restricted male-line turkeys were more active than ad libitum-fed birds of both sexes. Restricted turkeys showed a high incidence of wall pecking. In the breeding period, about 0.4 of the observations of male-line males were of strutting behaviour whereas traditional male turkeys showed no strutting behaviour at the end of the breeding period. 3. The heterophil lymphocyte ratio (HLR) and the proportion of basophils were not increased in food-restricted turkeys. The HLR was relatively low in traditional birds, compared with male-line turkeys during the rearing period. 4. Plasma corticosterone concentrations were increased by food restriction during the rearing period. Corticosterone concentrations were relatively high in traditional turkeys at 4 and 8 weeks of age only. 5. Plasma lactate dehydrogenase (LIDH) activity was higher from 12 to 24 weeks of age in ad libitum-fed male-line turkeys and was consistent with mortality from cardiovascular disease in this group of turkeys. The pattern of activity of aspartate transaminase was similar, and alkaline phosphatase was inversely related to that of LDH. 6. It was concluded that turkeys may be better able to adjust physiologically to the demands of food restriction than broiler breeders and that there were few deleterious consequences of restricting male turkeys after 18 weeks of age. Male-line turkeys were less active than traditional turkeys.

Assessment of pain during locomotion and the welfare of adult male turkeys with destructive cartilege loss of the hip joint.

1. An assessment was made of the potential pain and stress from musculo-skeletal disease at 54 weeks of age in large male-line turkeys fed ad libitum or on restricted amounts of food. Males from traditional turkey lines were used as a negative control. 2. Traditional turkeys were fed ad libitum and male-line turkeys were fed ad libitum or restricted to 0.5 during rearing and subsequently to 0.8 of sex-specific ad libitum-fed body weight or fed ad libitum to 18 weeks and 0.8 of ad libitum thereafter. 3. Pain was assessed at 54 weeks of age by the change in number of steps taken by turkeys with or without musculo-skeletal disease after a course of betamethasone, a steroid anti-inflammatory agent with analgesic properties. 4. The numbers of steps over 24 h were recorded using a pedometer and were similar in all 4 treatments before and after treatment with the analgesic. It was concluded that there was no evidence for pain associated with musculo-skeletal disease among the turkeys in this experiment. 5. Musculo-skeletal disease was not associated with raised heterophil-lymphocyte ratio, a recognised index of stress.

UK survey of broiler ascites and sudden death syndromes in 1993.

1. The mean incidence of deaths from ascites in the UK in 1993 was 1.4% (0.7% in 1991 and 0.9% in 1992) and 0.8% from sudden death syndrome (SDS). In total, the economic loss to the UK Broiler Industry in 1993 as a result of these 2 conditions was 24 Pounds M. 2. Clear geographical differences emerged in the occurrence of ascites, with, not only the lowest incidences being observed in Northern Ireland, but also the peak of the mortality from ascites occurring much later in the rearing cycle than in other regions on the mainland. 3. In all regions the incidence of SDS was lower than that of ascites but the reason for this disparity remains to be established. 4. Some of the variables associated with the road transportation of day-old chicks from the hatchery to the farm appeared to influence the incidence of ascites. These included distance or time travelled, stocking density, internal lorry temperature and the length of time the lorry was heated before transport as well as the time the shed was heated before chick arrival. Temperature was also an important factor during growth (brooding and finishing). 5. Negative pressure-powered ventilation was preferred in most organisations but more ascites was seen with positive pressure ventilation. However, the lowest incidence of ascites occurred with natural ventilation. There was more ascites relative to shed orientation when the wind direction was from the west compared to the east. 6. This survey identifies the extent of the problem of broiler ascites in the UK and also highlights the importance of good management control of day-old chicks, not only following placement, but even before their arrival on the farm.

A preliminary estimate of the heritability of plasma troponin T in broiler chickens.

1. Male and female broiler chickens of a pure line were selected over one generation for low or high plasma, cardiac-derived troponin T concentrations at 12 h of age. 2. Heritability of plasma troponin T was moderately high (h2 = 0.38 +/- 0.06), and there was no difference in mean body weights of parents (G0) of the 2 lines at 4 and 19 weeks of age. 3. This preliminary study suggests that broiler breeder companies will be able to select for resistance against heart damage and ascites.

Allograft responses can interfere with the development of immunity against Theileria annulata following vaccination with parasite infected cell lines.

Theileria annulata macroschizont-infected cell lines are successfully used as vaccines in several countries. The inoculated animals produce a strong allogeneic response against the MHC antigens of the immunizing cell line followed by an anti-parasite response. Immunity against the parasite wanes in the absence of challenge and re-immunization is sometimes recommended. However, it is not known if allogeneic responses generated by the first immunization with a T. annulata infected cell line will interfere with the boosting of immunity against the parasite at the time of re-immunization with the same cell line. Animals were primed against MHC antigens by skin grafting, followed by immunization with a T. annulata infected cell line prepared from the skin donor. A strong anti-MHC response was produced. This interfered with parasite transfer and the development of an anti-parasite immune response; the effect was more marked when a low vaccine cell dose was used. There was a negative correlation between the ease of isolating infected cells from the animals after cell line immunization, and the subsequent response to challenge. Where no cell lines could be isolated, the animals were fully susceptible to sporozoite challenge. These observations are of immediate importance in endemic areas where cell lines of T. annulata schizonts are being used as vaccines to control the disease.

Characterisation of embryonic cardiac-derived troponin T in broiler chicks bled one to 168 hours after hatching.

Troponin T, a cardiac-specific protein released only from damaged or injured heart tissue and cells, was measured in the sera from fowl chicks bled one, 12, 24, 48, 96 and 168 hours after hatching. A peak troponin T response was observed 12 hours after hatching in two experiments conducted six months apart. In the second experiment the heterophil/lymphocyte (H/L) ratios were also increased at one and 12 hours after hatching. The data suggest that the troponin T response in chicks bled 12 hours after hatching, together with the raised H/L ratios at the same age, may indicate a physiological stress reaction to the process of hatching, rather than a process which is under direct genetic control.

Clinical detection of sarcopenic obesity by bioelectrical impedance analysis.

To assess whether bioelectrical impedance analysis (BIA) provides clinically useful information on body composition beyond that obtained from measuring height and weight, we clinically classified 306 obese patients (233 females and 73 males) into tertiles of increasing fat-free mass estimated by BIA. Because fat-free mass by BIA is an estimate of lean body mass, the lowest tertile was clinically defined as sarcopenic obesity (reduced lean body mass), as contrasted with proportionate or muscular obesity in the next two tertiles. Fat mass in patients in each of the above tertiles based on BIA was then compared with fat mass estimated by using the equations of Garrow and Webster with body mass index (weight/height2). BIA-estimated fat mass was 4.3 kg greater in the sarcopenic group (n = 102) than predicted from body mass index. Fat mass predicted by BIA in the proportionate (n = 102) and muscular (n = 102) groups differed by less than the SEE of fat mass predicted by BMI. In premenopausal women at increased risk of breast cancer BIA showed a high prevalence of sarcopenic obesity (28/30) in these women at normal body mass indexes. Thus, BIA may be clinically useful for demonstrating sarcopenic obesity, but additional studies are needed to determine the metabolic and clinical significance of sarcopenic obesity.

Evidence of ultracytochemical mitochondria-derived hydrogen peroxide activity in myocardial cells from broiler chickens with an ascites syndrome.

The location of the cytotoxic reactive oxygen metabolite hydrogen peroxide was investigated ultracytochemically in broiler chickens which had been reared at sea level and had spontaneous hypoxia-induced ascites syndrome. In the ascitic birds the activity was located within the mitochondrial matrices of the cardiomyocytes, whereas in flock-mate control birds it was membrane-bound. Little or no activity was present in negative control material, which was prepared by detoxification with catalase, by extraction with acetone, by the omission of NADH and by the replacement of NADH by NADPH. The study demonstrated that there was probably hydrogen peroxide activity in the mitochondria of the ascitic birds.

Relationships between the degree of food restriction and welfare indices in broiler breeder females.

1. Broiler breeder females were fed ad libitum, or according to a commercial food restriction programme or to gain 0.85, 0.70, 0.55, 0.40 or 0.25 of the body weight of ad libitum-fed birds. Several indices of the welfare of the birds were assessed at 3-weekly intervals to 18 weeks of age and related to body weight by regression analysis. Results for 6, 12 and 18 weeks of age are presented in detail. 2. Water intake was consistently higher in the 0.25, 0.40 and commercial restriction treatments. 3. There was a negative curvilinear relationship at each age group between body weight and the heterophil-lymphocyte ratio and plasma corticosterone concentration. 4. There was a positive relationship between the plasma concentration of creatine kinase and body weight at 12 and 18 weeks of age. The relationships between body weight and the plasma activity of alkaline phosphatase and aspartate transaminase changed with the age and there were no differences between treatments for lactate dehydrogenase. 5. The time spent resting increased with body weight at each age. The relationship between time spent preening and body weight changed with age whereas that for oral activities was similar among restricted birds at 6, and among all treatments at 12 weeks of age. At 18 weeks there was an increase in oral activities with decreasing body weight. 6. Fearfulness was positively related to body weight. The response of the comb to phytohaemagglutinin injection was similar in all treatments and the antibody titre to injections of sheep red blood cells was curvilinear. 7. A principal components analysis of all measured traits at 6, 12 and 18 weeks of age was conducted. Most of the variables were redundant but at least one from each of the different classes of welfare indices was retained at 6 and 12 weeks of age. 8. It was concluded that a body weight during rearing in the range of 0.5 to 0.85 of ad libitum might provide for optimum welfare of broiler breeder females.

Plasma viscosity values and the relationship with age and sex in normal commercial broiler and layer strains of chickens.

1. The plasma viscosity values of normal commercial broiler and layer strains of chicken were measured in relation to age and sex. 2. In both broilers and layers plasma viscosity values decreased at 2 weeks of age; probably reflecting the period of change from maternal plasma protein to the bird's self-synthesised proteins. 3. There was a progressive rise in plasma viscosity in both strains and sexes with age. The increase was greatest in female layers at 17 weeks of age before lay. 4. There was no overall significant difference in viscosity values between fresh and frozen-stored plasma samples.

Identification of tissue hypoxia in the livers of ascitic and hypoxia-induced broilers using trypan blue.

1. The perfusion of livers with the vital dye trypan blue was performed to test for evidence of tissue hypoxia in 3 groups of young broiler chickens, namely, ascitic, hypoxia-induced and controls. 2. Hepatocytes that stained with trypan blue were considered to be dead or dying before fixation and represented damaged cells. 3. The proportion of trypan blue-stained hepatocytes in the livers of ascitic birds was slightly less than half that observed in the hypoxia-induced birds but significantly more than the proportion of stained cells observed in control birds. 4. Liver damage in the ascitic birds was also assessed biochemically by an altered enzyme profile. 5. The study demonstrated that increased trypan blue uptake in the livers of ascitic birds reared at sea-level may be the consequence of hypoxia stress caused by reduced oxygen utilisation.

Serum troponin T values in 7-day-old hypoxia-and hyperoxia-treated, and 10-day-old ascitic and debilitated, commercial broiler chicks.

Troponin T is a cardiac-specific protein forming part of the contractile apparatus of striated muscle, and in humans it is a new, sensitive and highly specific indicator of early myocardial damage in 'at risk' patients. Serum troponin T values were investigated in 7-day-old hypoxia- and hyperoxia-treated and 10-day-old ascitic and debilitated commercial broiler chicks. The results showed that there was a significant increase in troponin T values in the hypoxic chicks (P< 0.05) compared with their normoxic flockmates. There was also a small, but insignificant rise in the troponin T values of the hyperoxia-treated chicks. The results confirm previous studies that myocardial damage in these young chicks is associated with hypoxia and that the injury caused permits the measurement of troponin T released from the cardiomyocytes. Significant increases in troponin T were also measured in 10-day-old ascitic (P < 0.05) and debilitated (P < 0.02) broiler chicks compared with age-matched control broilers. In both age-groups of birds, the arterial pressure index, a measurement of right ventricular hypertrophy caused by chronic pulmonary hypertension, was similar with the respective control values and yet the troponin T concentrations were significantly different. These results demonstrate the importance of this assay in young broiler chickens as a marker of early myocardial damage in these birds. It is proposed that this assay for troponin T could be a valuable prognostic tool in future genetic selection programmes to reduce the degree of susceptibility to hypoxia and with it the incidence of ascites in young broilers.

Serum troponin T concentrations in two strains of commercial broiler chickens aged one to 56 days.

Troponin T is a specific and sensitive serological indicator of acute myocardial infarction in human patients. The concentration of serum troponin T was measured by an ELISA technique in two strains of healthy commercial broiler chickens (Cobb 500 and Ross I) aged between one and 56 days. The concentrations of cardiac-derived troponin T in day-old Cobb and Ross chicks were 5.74 and 8.35 ng ml-1, respectively, and much higher than in 14-day-old chicks. Between 21 and 56 days, the values were consistently lower than the mean troponin T concentration of 0.20 ng ml-1 reported previously in a group of healthy 30-day-old broilers. All the other heart measurements, including the arterial pressure index, were within normal limits. The high troponin T concentrations after hatching are probably due to an embryonic isoform that rapidly becomes replaced by an adult isoform by three weeks of age. The data suggest that in healthy birds, there is an inverse relationship between troponin T concentrations and age.

Potential role of serum troponin T in cardiomyocyte injury in the broiler ascites syndrome.

1. Cardiac troponin T is a recently developed serological marker used as a sensitive diagnostic tool for early myocardial damage in 'at risk' human patients. 2. Serum troponin T values were measured in young 30-d-old broilers with ascites and in healthy age-matched flockmates. 3. The data showed a significant increase (P < 0.001) in troponin T values in ascitic broilers compared with control birds. A similar increase in the arterial pressure index in ascitic birds indicated a good positive correlation at this age. 4. The results suggest that this new assay cross-reacts with chicken cardiac troponin T antigen and that it may be an important indicator of myocardial cell damage for use in future genetic selection programmes in the combat against ascites.

Haematology and blood composition at two ambient temperatures in genetically fat and lean adult broiler breeder females fed ad libitum or restricted throughout life.

1. Genetically fat and lean adult broiler breeder females were fed ad libitum or restricted throughout life. At one year of age, comparisons of blood viscosity and haematology and changes in blood chemistry after exposure to thermal stress were conducted. 2. Whole blood viscosity was more than twice as high, and plasma triglyceride and haemoglobin concentrations were over 30% higher in fat line than in lean line females fed ad libitum or in restricted birds of both genotypes. 3. Mean cell haemoglobin concentration was higher and mean cell volume lower in fat compared with lean line females. 4. Food restriction was associated with lower plasma triglyceride concentrations, lower numbers of heterophils and monocytes and a lower heterophil-lymphocyte ratio. 5. Fat line birds had a higher blood pCO2 and lower pH than lean line birds. 6. Thermal stress was associated in ad libitum-fed birds with a rise in blood pH and a decrease in pCO2, and in restricted birds with a decline in blood pH and an increase in pCO2. 7. Blood creatine kinase activity increased in all groups under thermal stress.

Role of insulin and norepinephrine in the hypertension of obesity.

The present study compares plasma norepinephrine (PNE), renin activity (PRA), aldosterone (PA), and insulin (RIAI) levels between 13 normotensive and 42 hypertensive obese subjects during weight maintenance, and in 19 of the 42 obese hypertensive subjects, these variables were measured during 16 weeks on a very low calorie diet (VLCD). Mean values for baseline RIAI and PNE were elevated in the 55 obese subjects compared to nonobese controls. However, when the normotensive and hypertensive groups were compared, mean values for PNE, PRA, PA, and RIAI were not different. In the 19 obese hypertensive subjects studied on the VLCD, there were significant reductions from baseline in mean body weight, blood pressure, RIAI, and PNE, but not for PRA or PA. Two phases of blood pressure, RAIA, and PNE responses to weight loss were noted. In the early phase (days 1-7), blood pressure and RAIA decreased dramatically, whereas PNE, PRA, and PA increased. During the late phase (weeks 2-16), further significant decreases in blood pressure and weight were accompanied by reductions in PNE (604 +/- 50 to 403 +/- 43 pg/mL, P < .01) and in RIAI (13.9 +/- 1.7 to 10.3 +/- 1.6 microU/mL, P < .05). As levels of insulin and norepinephrine were similar in normotensive and hypertensive obese individuals during weight maintenance, they may not contribute to the hypertension associated with obesity. During weight loss, however, the temporal changes in blood pressure, insulin, and norepinephrine suggest their mediation of the hypotensive response.