Increasing the incubation temperature between embryonic day 7 and 10 has no influence on the growth and slaughter characteristics as well as meat quality of broilers

Avian embryogenesis can be manipulated by alteration of the temperature during incubation of the brooding egg. Investigations in turkeys showed that a higher temperature during early embryogenesis positively affects the myogenesis accompanied with a higher muscle fibre number (MFN). The aim of this study was to transfer this result to broiler and to investigate if an alteration of the temperature also affects the meat quality after slaughter of the birds. Therefore brooding eggs of the Cobb 500 broiler genetic were either incubated at 37.5°C during the whole incubation period (at normal temperature (NT)), or at 38.5°C during embryonic day (ED) 7 to 10 (at high temperature (HT)). After hatch the chicks were sexed and reared up to an age of 36 days in an experimental stable. Growth and feed conversion properties were determined during this period. After slaughter different meat quality characteristics as well as the muscle microstructure were analysed. The hatch rate and chick weight did not differ between the broiler of the NT and HT group. After 36 days the final body weights and the cumulative feed conversion rates were not different in the NT and HT groups. No differing results were obtained with regard to the slaughter, breast and leg weights of the NT and HT animals. Considering the gender of the animals no differences in the slaughter characteristics could be determined although the carcass and breast weights of the HT cocks were tendentially higher. The muscle fibre areas and MFNs in the breast muscles of the NT and HT cocks did not differ significantly and were in the range of the HT hens. Only the NT hens had significantly larger muscle fibres and less MFN than the other animals. With regard to the meat quality characteristics no clear differences of the pH, electrical conductivity (EC) and colour (L*a*b*) values were found. The L*a*b* values in the investigated breast muscles of all broilers usually increased during ageing. The increase of the incubation temperature had no impact on the hatch, growth, slaughter and meat quality characteristics of the broiler except for the tendentially higher carcass and breast weights of the HT cocks. However, the decrease of the fibre areas in the HT hens is an interesting effect of using a higher incubation temperature, which needs to be considered when implicating further investigations.     

The Influence of Naringin or Hesperidin Dietary Supplementation on Broiler Meat Quality and Oxidative Stability

An experiment was conducted to examine the effects of supplementing broiler feed with hesperidin or naringin, on growth performance, carcass characteristics, breast meat quality and the oxidative stability of breast and thigh meat. Two hundred and forty 1-day-old Ross 308 broiler chickens were randomly assigned to 6 groups. One of the groups served as a control (C) and was given commercial basal diets, whereas the other five groups were given the same diets further supplemented with naringin at 0.75 g/kg (N1), naringin at 1.5 g/kg (N2), hesperidin at 0.75 g/kg (E1), hesperidin at 1.5 g/kg (E2) and a-tocopheryl acetate at 0.2 g/kg (E). At 42 days of age, 10 chickens per treatment group were slaughtered for meat quality and oxidative stability assessment. No significant differences were observed among groups in final body weight, carcass weight and internal organs weights (P>0.05) apart from liver that decreased linearly with increased levels of naringin (P-linear<0.05). Regarding the breast meat quality parameters, only redness (a*) value was higher in E1 and N1 group compared to VE group (P<0.05), while all the others i.e. shear values (N/mm²), pH₂₄, cooking loss (%) and L* and b* color parameters were not significantly different among groups (P>0.05). Measurement of lipid oxidation values showed that after hesperidin and naringin dietary supplementation, malondialdehyde values decreased in tissue samples in a dose depended manner (P-linear<0.05). In conclusion, hesperidin and naringin, positively influence meat antioxidative properties without negative implications on growth performance and meat quality characteristics in poultry, thus appearing as important additives for both the consumer and the industry.     

Mitochondrial respiratory and antioxidative enzyme activities in turkey meat

Meat quality and (anti)oxidative metabolism of m. pectoralis superficialis (MPS), m. gastrocnemius (MG) and m. iliotibilialis lateralis (MIL) from turkey toms were analysed. After slaughter, pH of MPS and MG decreased and electrical conductivity of the MPS increased. The MG had generally higher pH values. The meat lightness (L) and redness (a) increased in MG and MPS after slaughter. The MPS always had higher L and lower a values. Mitochondrial respiratory activities (MRA) were higher in the MIL than the MPS. The activities of superoxide dismutase (SOD) and glutathione peroxidase, analysed in the MPS, increased and the glutathione reductase activity decreased after slaughter. Meat samples with lower pH24 h p.m. had higher drip loss and L values. The MRA were tendentially lower and the SOD activities higher in these samples. These results indicate a relation between the meat quality, the antioxidative metabolism and mitochondrial respiration.     

Temperature alterations during embryogenesis have a sex-dependent influence on growth properties and muscle metabolism of day-old chicks and 35-day-old broilers

Broiler eggs were either incubated at 37.8°C during the whole incubation period (control), or at higher (38.8°C, group H) and lower temperatures (36.8°C, group L) from embryonic day (ED) 7 up to ED 10 (ED 7 to 10) or from ED 10 up to ED 13 (ED 10 to 13). Before and after this temperature treatment the eggs were incubated at 37.8°C. The day-old chicks were weighted, sexed and fed up to day 35. On days 1 and 35 samples were taken from the breast and leg muscles for analyzing of the mitochondrial respiratory activity (MRA) and from the breast muscles for analysis of the cross-sectional areas (CSA) and the glycogen phosphorylase (GP), phosphofructokinase (PFK), lactate dehydrogenase (LDH), citrate synthase (CS) and cytochrome oxidase (COX) activities. Statistical analysis showed that treatment (control, group H, group L), sex and their interaction, but not the treatment period (ED 7 to 10; ED 10 to 13), significantly influenced the results. Group H chicks had lower (P⩽0.05) body and heart weights but higher (P⩽0.05) liver weights, CSA values, leg MRA as well as PFK, LDH, CS, GP and COX activities compared with the group L chicks. The results of the control chicks differ (P⩽0.05) from those of the group H (body, heart weight, COX), the group L chicks (liver weight, PFK, LDH, CS, GP) or the birds of both other groups (CSA). The group H broiler had higher (P⩽0.05) body and leg weights as well as LDH, CS, COX and GP activities than the group L broilers. The BWs and the LDH and GP results of the control broiler differ (P⩽0.05) from those of both other groups or from the results of the group H (CS) and group L broiler (COX). Female broilers had lower (P⩽0.05) body, breast and leg weights, but higher (P⩽0.05) CSA, LDH, CS and GP activities than the male animals. Analysis of treatment×sex interaction showed that group H hens had higher (P⩽0.05) body and breast weights, LDH and GP activities compared with the group L hens, whereas in the male broiler no effect of the interaction could be found, except for the lower (P⩽0.05) CSA values in the group H than group L cocks. The treatment effects are probably due to altered embryonic activity and related molecular mechanisms. The sex-related differences in the broiler indicate that these alterations already occur in the embryos and chicks, but become significant with the sexual dimorphism after hatch.     

Effect of caponisation on growth and on carcass and meat characteristics in Castellana Negra native Spanish chickens

This paper analyses the effect of caponisation at 8 weeks on growth and on carcass and meat characteristics of Castellana Negra chickens slaughtered at 29 weeks. Caponisation did not result in weight improvements as compared with uncastrated birds. No changes were observed in the growth rate or in the parameters determining the point of inflection in the growth curve (sexual maturity). Regarding carcass characteristics, castration resulted in a wider breast angle and heavier pectoral muscles in caponised birds than in uncastrated birds, but with no differences in thigh and drumstick weight and length. Capon meat showed a higher fat content than that of cocks, making it juicier and less fibrous. No differences were found in fatty acid content (C 14:0, C 18:0, C 18:1 and C 18:2). Nor were there any differences in colour measurements, pH or water loss from the meat. While cocks' thighs + drumsticks were found to be tougher than their breasts, there were no such differences in capons because after castration, thigh + drumstick meat became more tender.     

Changes in muscle cell cation regulation and meat quality traits are associated with genetic selection for high body weight and meat yield in broiler chickens

Between-breed genetic variation for muscle and meat quality traits was determined at eight weeks of age in 34 lines of purebred commercial broiler and layer lines and traditional breeds (categories) of chickens. Between-breed genetic variation for plasma ion concentrations and element concentration in muscle dry matter and ash were determined. Plasma from broilers had higher concentrations of Na⁺, K⁺, Mg⁺⁺, total and free Ca⁺⁺ and lower free:total Ca⁺⁺ than plasma from layer and traditional lines. Muscle from broilers contained more Na and higher concentrations of K, Mg and Ca per mg of ash but not of dry matter compared with layer and traditional lines. In comparison with layer and traditional lines, broiler genotypes were over three times heavier, their plasma creatine kinase activity (CK), a marker of muscle tissue damage, was higher, their breast muscle colour was lighter (L*) and less red (a*) and yellow (b*) in appearance, the initial and final pH of their muscles were lower, the pH change was higher and their breast muscle was more tender. Thus, genetic selection for broiler traits has markedly altered cation regulation in muscle cells and may be associated with changes in muscle cell function and the development of pathology and meat quality problems.     

The Retention of Cadmium and Selenium Influence in Fowl and Chickens of F1 Generation

The retention of cadmium and selenium influence on Cd retention in the muscle, liver and kidneys of hens, chickens and in eggs was studied. Cadmium (Cd) as cadmium chloride (CdCl(2)) and selenium (Se) as sodium selenite (Na(2)SeO(3)) were added to feed at dosages: group 0-control, group 1-20 mg/kg Cd, group 2-30 mg/kg Cd + 4 mg/kg Se. The birds were exposed to Cd for 8 weeks. Cadmium level in hens and cocks was found highest in the kidneys, followed by the liver and muscle. Se supplementation resulted in Cd increase in the muscle tissue and in the reduction of Cd content in the liver and in significant decrease in the kidneys (p < 0.05). A higher Cd level in the yolk and lower in the white was noted in both experimental groups. Nonsignificant increase of Cd in eggs was noted in experimental groups with Se supplementation. Level of cadmium in organs of 7-day-old chicks hatched from Cd-treated hens in both experimental groups was low but the tendency to accumulate preferentially the Cd in the liver and kidneys was recorded. Supplementation of selenium in hens and cocks was not reflected in the decrease of Cd in these two organs of F(1) chickens but was reflected in increase in the muscle. In spite of relatively high Cd levels in the organs of layers no layer-egg-chickens transfer was observed. It was confirm that kidneys and liver are organs more attacked by dietary cadmium than muscle. Supplementation of low dose of Se resulted in decrease of cadmium deposition in analyzed organs.     

Metabolic differentiation of red and white skeletal muscle in vivo and in monolayer culture

Cytochrome oxidase, succinate oxidase and lactate dehydrogenase were compared in: (a) leg and breast muscle from 11-19-day-old chick embryos; and (b) 2, 6, 10 and 14-day-old primary cell cultures established from myoblasts of embryonic leg and breast muscle. Cytochrome oxidase, succinate oxidase and lactate dehydrogenase activities were higher (48.8, 65.4, 277.6%, respectively) in leg muscle after 19 days in ovo. Cytochrome and succinate oxidase activities were higher (111.3, 48.1%, respectively) in leg muscle cell cultures after 14 days in vitro. The data represent evidence for intrinsic developmental patterns for certain enzymes.     

Black soldier fly as dietary protein source for broiler quails: apparent digestibility,excreta microbial load,feed choice,performance, carcass and meat traits

In order to expand with validated scientific data the limited knowledge regarding the potential application of insects as innovative feed ingredients for poultry, the present study tested a partial substitution of soya bean meal and soya bean oil with defatted black soldier fly (Hermetia illucens) larvae meal (H) in the diet for growing broiler quails (Coturnix coturnix japonica) on growth performance, mortality, nutrients apparent digestibility, microbiological composition of excreta, feed choice, carcass and meat traits. With this purpose, a total of 450 10-day-old birds were allocated to 15 cages (30 birds/cage) and received three dietary treatments: a Control diet (C) and two diets (H1 and H2) corresponding to 10% and 15% H inclusion levels, respectively (H substituted 28.4% soya bean oil and 16.1% soya bean meal for H1, and 100% soya bean oil and 24.8% soya bean meal for H2, respectively). At 28 days of age, quails were slaughtered, carcasses were weighed, breast muscles were then excised from 50 quails/treatment, weighed, and ultimate pH (pHu) and L*, a*, b* colour values were measured. Breast muscles were then cooked to assess cooking loss and meat toughness. For the digestibility trial, a total of 15 28-day-old quails were assigned to the three feeding groups. The excreta samples were subjected to chemical and microbiological analysis. The same 15 quails were then simultaneously provided with C and H2 diets for a 10-day feed choice trial. Productive performance, mortality and carcass traits were in line with commercial standards and similar in all experimental groups. With the exception of ether extract digestibility, which was lower in H1 group compared with C and H2 (P=0.0001), apparent digestibility of dry matter, CP, starch and energy did not differ among treatments. Microbial composition of excreta was also comparable among the three groups. Feed choice trial showed that quails did not express a preference toward C or H2 diets. Breast meat weight and yield did not differ among C, H1 and H2 quails. Differently, the inclusion of H meal reduced meat pHu compared with C. In conclusion, this study demonstrated that H. illucens larvae meal can partially replace conventional soya bean meal and soya bean oil in the diet for growing broiler quails, thus confirming to be a promising insect protein source for the feed industry. Further research to assess the impact of H meal on intestinal morphology as well as on meat quality and sensory profile would be of utmost importance.     

Carcass and meat quality traits of chickens fed diets concurrently supplemented with vitamins C and E under constant heat stress

The objective of this study was to determine if a diet supplemented simultaneously with vitamins C and E would alleviate the negative effects of heat stress, applied between 28 and 42 days of age, on performance, carcass and meat quality traits of broiler chickens. A total of 384 male broiler chickens were assigned to a completely randomized design, with a 2×3 factorial arrangement (diet with or without vitamin supplementation and two ambient temperatures plus a pair-feeding group) and 16 replicates. Chickens were kept in thermoneutral conditions up to 28 days of age. They were then housed in groups of four per cage, in three environmentally controlled chambers: two thermoneutral (22.5 and 22.6°C) and one for heat stress (32°C). Half the chickens were fed a diet supplemented with vitamins C (257 to 288 mg/kg) and E (93 to 109 mg/kg). In the thermoneutral chambers, half of the chickens were pair-fed to heat stressed chickens, receiving each day the average feed intake recorded in the heat stress chamber in the previous day. Meat physical quality analyses were performed on the pectoralis major muscle. No ambient temperature×diet supplementation interaction effects were detected on performance, carcass, or meat quality traits. The supplemented diet resulted in lower growth performance, attributed either to a carry-over effect of the lower initial BW, or to a possible catabolic effect of vitamins C and E when supplemented simultaneously at high levels. Heat stress reduced slaughter and carcass weights, average daily gain and feed intake, and increased feed conversion. Growth performance of pair-fed chickens was similar to that of heat stressed chickens. Exposure to heat stress increased carcass and abdominal fat percentages, but reduced breast, liver and heart percentages. Pair-fed chickens showed the lowest fat percentage and their breast percentage was similar to controls. Heat stress increased meat pH and negatively affected meat color and cooking loss. In pair-fed chickens, meat color was similar to the heat stressed group. Shear force was not influenced by heat stress, but pair-fed chickens showed the tenderest meat. In conclusion, reduction in growth performance and negative changes in meat color in heat stressed chickens were attributed to depression in feed intake, whereas negative changes in body composition, higher meat pH and cooking loss were credited to high ambient temperature per se. Diet supplementation with vitamins C and E as antioxidants did not mitigate any of these negative effects.     

鸡肉肌苷酸和肌内脂肪等肉品风味性状遗传参数的估计

对鸡肉肌苷酸（Inosine-5¢-Monophosphate,IMP）和肌内脂肪（Intramuscular fat,IMF）等重要肉品风味性状的遗传参数进行了估计,旨在从遗传理论上为确定鸡肉风味品质性状的选育方法提供依据。采用MTDFREML方法对1069只90日龄北京油鸡公鸡的相关性状的遗传力和遗传相关进行了估计,结果表明,胸肌IMP和IMF含量属中等偏低遗传力性状（h2=0.23,0.10）,腹脂重(AFW)、胸肌重(BMY)、胸肌率(BMR)、腿肌重(LMY)、体重(BW)、鸡冠重(CW)和鸡冠率(CWP)的遗传力较高（h2=0.56～0.79）,腹脂率(AFP)、腿肌率(LMR)、睾丸重(TW)和睾丸率(TWP)等性状的遗传力分别为0.24、0.32、0.39和0.35。IMP与胸肌率、腿肌率和尾脂厚呈较低度的表型正相关,与其他性状无明显表型相关;IMF与体重、腹脂率、尾脂厚和脂带宽呈一定程度的表型正相关（rP=0.11～0.33）。IMP与体重和鸡冠率呈中等以上程度的遗传负相关（rA=-0.38,-0.62）,与胸肌率呈较高水平的遗传正相关（rA=0.57）;IMF与体重和腹脂重则呈高度遗传正相关（rA=0.7 5,0.66）,与腹脂率和鸡冠率呈中等水平遗传正相关（rA=0.32,0.40）;IMP与IMF之间呈中低水平的遗传正相关（rA =0.27）。据此推断,可以利用家系法对IMP和IMF含量进行选择提高。     

Effect of Sex and Dietary Organic Zinc on Growth Performance, Carcass Traits, Tissue Mineral Content, and Blood Parameters of Broiler Chickens

Zinc (Zn) is an essential mineral for animal development and function. A study was carried out to evaluate the effect of sex and dietary organic zinc (OZ) on growth performance, carcass traits, tissue mineral content, and blood parameters of broiler chickens. A total of 240 1-day-old male and 240 female broiler chicks (Cobb × Cobb) were assigned to two dietary levels of OZ (2 × 2 factorial) with six replicates per treatment (20 birds/replicate pen). The OZ supplementation levels were 0 and 25 ppm. Results showed that OZ supplementation did not affect the growth performance of male and female broilers, but the males showed significantly better (P < 0.05) growth performance than females did. Similarly, OZ supplementation did not affect the thickness of both the back and thigh skin of male and female broilers; however, males had thicker skin than females. Dietary OZ supplementation did not affect collagen contents in the skin and meat samples. Male broilers had higher skin collagen contents than females, but no sex difference was found in meat collagen contents. OZ supplementation did not affect the shear force values of skin and meat samples. Male broilers had higher shear force values of back skin than females, but not in the meat samples. Dietary OZ supplementation increased (P < 0.05) the thigh meat Zn content in both sexes. The plasma Ca content was significantly (P < 0.05) increased by dietary OZ supplementation; however, other blood parameters were not affected by dietary OZ supplementation. Males had higher plasma glucose and cholesterol content than females. It is concluded that dietary OZ supplementation at the level of 25 ppm does not affect the growth performance and skin quality of broiler chickens but increases the Zn content in thigh meat and Ca content in plasma of broiler chickens. Male broilers had better growth performance and skin quality than females.     

Antioxidative responses to different altitudes in leaves of alpine plant Polygonum viviparum in summer

Mountain environmental stresses result in increased formation of hydrogen peroxide (H₂O₂) and accumulation of malondialdehyde (MDA) in leaves of Polygonum viviparum. The activities of several antioxidative system enzymes such as superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), peroxidase (POD, EC 1.11.1.7), glutathione reductase (GR, EC 1.6.4.2), dehydroascorbate reductase (DHAR, EC 1.8.5.1) and the contents of several non-enzymatic antioxidants such as reduced form of ascorbate (ASC), dehydroascorbate (DHA), reduced glutathione (GSH), and oxidized glutathione (GSSG) were investigated in leaves of P. viviparum, which were collected from three altitudes (2,200, 3,200, and 3,900 m) of Tianshan Mountain in China. The activities of these four antioxidative enzymes were accompanied by increases of H₂O₂ levels from 2,200 to 3,200 m. However, the activities of CAT and POD were decreased, whereas the activities of SOD and GR continually increased at 3,900 m. Analyses of isoforms of SOD, CAT, POD, and GR showed that the leaves of P. viviparum exposed different altitude conditions are capable of differentially altering the intensity. Additionally, two new isoforms of SOD were detected at 3900 m. A continual increase in the ASC, ASC to DHA ratio, GSH and GSH/[GSH + GSSG] ratio, and the activity of DHAR were observed in leaves of P. viviparum with the elevation of altitude. These results suggest that the higher contents of ASC, GSH as well as an increase in reduced redox state may be essential to antioxidation processes in the leaves of P. viviparum, whereas antioxidant enzymes system is a cofactor in the processes.     

Effect of caponisation on physicochemical and sensory characteristics of chickens

The meat fats content associated to nutritional and sensory characteristics are the most important concerns of consumers. To study the effect of caponisation on the meat quality of two different breed chickens, slaughtered at 18 weeks of age, raised under the same conditions, the physicochemical and sensory characteristics of capons (castrated males at 8 weeks of age) and roosters’ meat of native Amarela Portuguesa and native Pedrês Portuguesa breeds were evaluated. Forty Amarela (20 roosters and 20 capons), 40 Pedrês (20 roosters and 20 capons) chickens, and also, six free-range chicken and six broilers were evaluated. The pH, water-holding capacity, Warner-Bratzler shear force, moisture content, ash, myoglobin, collagen, CP, total fat and fatty acids profile were evaluated in breast and leg meat, according to standard procedures. Leg meat capon showed greater intramuscular fat content (P⩽0.05), monounsaturated fatty acids (MUFA) and CP (P⩽0.001) than leg roosters. Caponisation increased the content of myoglobin and MUFA (P⩽0.05) and reduced the moisture content in the leg (P⩽0.05). The main fatty acids found were oleic acid (C18:1), palmitic acid (C16:0) and linoleic acid (C18:2). The greatest value of C18:1 was observed in capon’s breast (P⩽0.01). Sensory analysis was made to compare the Amarela and Pedrês meat with a free-range chicken and a broiler. The sensory taste panel classified the capon’s meat (Amarela and Pedrês) as juicier, less fibrous and tougher than rooster’s meat. The broiler was in general juicier, tenderer and less fibrous than the other birds. The results of sensory analysis complement those obtained in physicochemical analysis, suggesting that caponisation promotes an overall improvement in meat quality.     

Oxidative stress and antioxidative defense in cephalopods: a function of metabolic rate or age?

Activities of the antioxidative enzymes superoxide dismutase (SOD), catalase, glutathione peroxidase (GPX) and glutathione reductase (GR) were measured in the cephalopods Sepia officinalis and Lolliguncula brevis. Maximal enzyme activities were higher in gill tissue than in the mantle musculature of both species. Activities were generally lower in tissues of L. brevis than in S. officinalis. Comparison with other ectothermic animals showed both cephalopod species to have a low enzymatic antioxidative status despite their high metabolic rate. Furthermore, changes in antioxidative enzyme activities were measured in the cuttlefish S. officinalis with increasing age. The concentrations of malondialdehyde (MDA) and lipofuscin were determined as indicators of lipid peroxidation. Investigated animals were between 1.5 months and over 12 months old. Changes of antioxidative enzyme activities with age were not uniform. SOD and GPX activities increased with age, while catalase activity declined. In contrast, GR activity remained almost unchanged in all age groups. The low level of antioxidative defense might allow for the significant age-induced rise in MDA levels in gills and mantle musculature and for the increase in lipofuscin levels in mantle and brain tissue. It might thereby contribute to increased oxidative damage and a short life span in these cephalopods.     

Regulation of myostatin expression is associated with growth and muscle development in commercial broiler and DMC muscle

Myostatin is a negative regulator of skeletal muscle growth. Muscle tissue is the largest tissue in the body and influences body growth. Commercial Avian broiler chickens are selected for high growth rate and muscularity. Daweishan mini chickens are a slow growing small-sized chicken breed. We investigated the relations between muscle (breast and leg) myostatin mRNA expression and body and muscle growth. Twenty chickens per breed were slaughtered at 0, 30, 60, 90, 120, and 150 days of age. Body and muscle weights were higher at all times in Avian chickens. Breast muscle myostatin expression was higher in Avian chickens than in Daweishan mini chickens at day 30. Myostatin expression peaked at day 60 in Daweishan mini chickens and expression remained higher in breast muscle. Daweishan mini chickens myostatin expression correlated positively with carcass weight, breast and leg muscle weight from day 0 to 60, and correlated negatively with body weight from day 90 to 150, while myostatin expression in Avian chickens was negatively correlated with carcass and muscle weight from day 90 to 150. The results suggest that myostatin expression is related to regulation of body growth and muscle development, with two different regulatory mechanisms that switch between days 30 and 60.     

Dynamics and distribution of radiocaesium in broiler chicken

The distribution and biological half-life of radiocaesium (¹³⁷Cs) in broiler chickens after three oral applications (in course of 1 day at the age of 14 days) of artificially contaminated feed mixture were studied. There was a rapid uptake of the orally administered ¹³⁷Cs (within a few hours) and also a rapid loss of ¹³⁷Cs which varied in the different organs (the initial biological half-life was: liver 0.6 day, intestine 0.6 day, breast meat 2 days, leg meat 1.2 days). More than one-half of the total administered ¹³⁷Cs activity (55%) was excreted from the body within the 1st day after dosage, and after 14 days more than 90% had been excreted. The highest accumulation of ¹³⁷Cs occurred in meat (50%–90%), and the proportion of total activity in breast and leg meat varied during decontamination. The transfer of radiocaesium from feed into the chicken body (measured as ratios of the ¹³⁷Cs activity concentrations in the organ to the ¹³⁷Cs activity concentration in the applied dose) 1 day after application was: 0.0220, 0.0294, 0.0216 and 0.0195 for breast meat, leg meat, intestine and liver, respectively. Significant differences between the values were demonstrated (P<0.05) except between those of breast meat and intestine. For the first 3 days there was a higher proportion of ¹³⁷Cs activity in leg meat, whereas from the 4th day a greater part of total activity was found in breast meat. The latter results were confirmed in a subsequent study. Data from this study suggest that if broiler chickens are contaminated by radiocaesium to a level of 5 kBq/chicken in the course of 1 day at the age of 14 days, then immediate feeding with uncontaminated feed mixture for 18 days should be effective in decontaminating the chicken's meat below the intervention levels for radiocaesium in animal products, i.e. below 1000 Bq ⋅ kg^–1. Received: 30 December 1996 / Accepted in revised form: 13 May 1997     

Assessment of the effect of alpha-galactosides injected during embryogenesis on selected chicken traits

The effect of different doses of alpha-galactoside (RFOs) preparations from Pisum sativum L. cv. Opal, injected into eggs during embryogenesis, on maintaining a high number of bifidobacteria, selected chicken broiler traits and the lipoprotein level of blood were studied. Two independent experiments were conducted. In the first, Ringer water solution containing 1.763 mg/egg of fructooligosaccharides (FOS) (I group), 2.1158 mg of pea RFO preparation containing 20% sucrose (II group) and 0.4232 mg of sucrose (III group) were injected into Hubbard broiler breeder eggs containing 12-day old embryos. Only Ringer water solution was applied to the eggs of the control group (IV group). The number of bifidobacteria determined in faeces of two-day old chicken of groups I and II was significantly higher in comparison with the sucrose and control groups. The high level ofbifidobacteria of groups I and II was maintained during 6 weeks. The dose of both preparations had no influence on the body weight, carcass, breast muscle, leg and abdominal fat ratio, total cholesterol, HDL and LDL serum concentrations. Broiler mortality and breast muscle cholesterol concentration was highest (P < 0.05) for the control group. On the other hand, the European Production Index, as well as serum triglycerides, were the lowest for this group. The second experiment was performed on Hybro G chicken breeder eggs. 0.69, 3.43 and 6.87 mg/egg of pea RFO preparation doses containing 20% sucrose were injected into the experimental groups. The number of bifidobacteria in the caecum and selected meat traits of broilers were determined. The results of this experiment confirmed that RFO injection in ovo causes the long-time maintenance of a high level ofbifidobacteria. The dose of the preparations does not have any effect on the selected broiler meat traits, except that the highest dose increases the percent of carcase in body weight. However, this dose reduced the hatchability of the treated embryos.     

Age-dependence of the antioxidative system in tobacco with enhanced glutathione reductase activity or senescence-induced production of cytokinins

Tobacco leaves of plants with enhanced glutathione reductase activity (GR46-27, Nicotiana tabacum L. cv. Samsun) or with autoregulated senescence-induced production of cytokinins (P_SAG12-IPT, N. tabacum L. cv. Wisconsin) were studied during the course of leaf development and senescence by measuring photosynthesis, chlorophyll and protein content, the antioxidants ascorbate, glutathione and α -tocopherol as well as the antioxidative enzymes ascorbate peroxidase (APX, EC 1.11.1.11), glutathione reductase (GR, EC 1.6.4.2) and superoxide dismutase (SOD, EC 1.15.1.1). The photosynthetic rate, as well as the chlorophyll and protein content, dropped with increasing leaf age after having reached a maximum at the end of the exponential growth phase. The concentrations of the water-soluble antioxidants ascorbate and glutathione fell continuously with age, whereas the concentration of the lipophilic α -tocopherol increased. The activities of the antioxidative enzymes APX, GR and SOD reached their maximum at the beginning of leaf development, but were reduced in senescing leaves. The age-dependent course of the measured leaf parameters in GR46-27 leaves was similar to the one in wild-type leaves, with the exception of an overall enhanced GR activity. In contrast, in old leaves of P_SAG12-IPT plants, which possess a much higher life span, the chlorophyll and protein content, the photosynthetic rate, the antioxidant concentrations of ascorbate and glutathione as well as the activities of the antioxidative enzymes were higher than in wild-type leaves. The results show that the capacity of the antioxidative system to scavenge radicals is sufficiently balanced with the plant metabolism, and its decline with increasing age is not the cause, but a consequence of senescence and ageing in plants.     

Options for the Production of Selenized Chicken Meat

A 42-day experiment was conducted to compare the effects of various levels of sodium selenite (SS) and Se-enriched yeast (SY) on chicken productivity, carcass traits, and breast Se concentration. Six hundred 1-day-old Cobb 500 broiler chicks were placed on 1 of 6 experimental treatments. The treatments consisted of feeding a diet without Se supplementation (basal diet) or basal diet with 0.6 mg/kg supplemented Se supplied by SS, SY, or a mix of the two (0.45 SS + 0.15 SY; 0.3 SS + 0.3 SY; 0.15 SS + 0.45 SY). Chicks in all Se-supplemented treatments had significantly higher final body weight and eviscerated weight than those on the basal diet (P < 0,05) and no significant differences were observed among selenium source (P < 0.05). Also, chicks in all Se-supplemented treatments had significantly higher Se contents in breast tissue than the control group (P < 0.05). Replacing SS by SY in the broiler diets resulted in increased concentrations of Se in the breast (P < 0.01). Strong correlations were found between breast Se concentrations and the level of SY supplementation of the broiler diet (r = 0.992). The results from this experiment indicate that SY is a superior source of selenium for the production of selenized meat, and can be used, without any detrimental effect on chicken performance, for adding nutritional value to broiler meat and thus safely improving human selenium intake.