Third Week Of Age Research Articles

Growth performance, carcass traits and physical properties of chicken meat as affected by genotype and production system

Abstract. The results of this study constitute a part of a project aiming at developing a cross-breed suitable for an extensive rearing system, utilising local biodiversity. Hybrids from mating a commercial broiler's male component (C) with Green-legged Partridgenous (GP) or Sussex (Sx) hens were compared with Cobb broilers. The study included 720 chickens of 3 genetic groups. Up to the third week of age, all birds were fed with balanced mixtures recommended for broiler chickens. From the fourth week, the mixture was weekly reduced by 10 % for the birds kept extensively (E). The deducted part was replaced with wheat bran, and from the seventh week with wheat. E groups had access to runs and received green fodder. Birds were slaughtered in 12th week of life. Carcass yield, giblets and proportion of carcass elements were estimated along with meat traits. The body weight at the 6th, 9th, 12th week of rearing and dissection results indicated a good suitability of Cobb chickens for an extensive rearing system. Hybrids were characterised by a considerably smaller proportion of breast muscle and slightly bigger of thighs and drumsticks, compared with Cobb, which could result from their greater motor activity. Results obtained by C × Sx and C × GP chickens, such as final body weight, proportions of abdominal fat and carcass elements, and appropriate value of meat traits, point at the usefulness of these hybrids as a meat-type chicken under extensive housing conditions. Darker colour of chicken meat, derived from C cocks and Sx or GP hens crossbred, can constitute an indicator for their carcasses' identification on the market.

EVALUATION OF TILMICOSIN IN TREATMENT OF MYCOPLASMA GALLISEPTICUM INFECTED CHICKENS

Tilmicosin is a macrolide antibiotic used in this study for management of experimentally infected chicken with Mycoplasma gallisepticum (Mg). Its efficacy was assessed by ELISA, re-isolation, lesion score and performance parameters. One hundred and ten day old chicks, tested negative M. gallisepticum, were deployed and equally divided into four groups in separate rooms. On the third week of age, group B was inoculated with 0.2ml of M. gallisepticum broth (108 CFU) into air sac. Group A was likewise infected but treated with tilmicosin phosphate in drinking water at fourth week of age. Group C treated in the same way but not infected while group D was left as control not infected/treated. On weekly basis swabs and serum samples were collected from each group for bacteriology and serology meanwhile morbidity, mortalities and weight gain were recorded. At the end of the experiment results showed that there was no significant differences in mean body gain of groups A, C and D 1606.61±5.79b, 1658.04±17.01a, 1624.60±17.36ab, respectively while there was significant reduction of ELISA antibody titer of group A which recorded 441.22±7.57bprobablereactors confirmed negative by bacteriological isolation comparingwithgroupB positive Mg at titer 1011.30±40.92a. It is proved that medication with tilmicosin phosphate in drinking water for 3 successive days was effective in curing of induced M. gallisepticum infection, moreover it was successful to overcome economic problem due to weight loss consequently marketability.

Effects of soluble ß-glucan on the immune responses of broiler chickens vaccinated with Newcastle disease vaccine and reared under heat stress

The main objectives of this study was to determine the influence of soluble β-glucan extracted from the cell wall of Saccharomyces cerevisiae on immune response of broiler chickens reared under heat stress .β-glucan 225μg/ml was supplemented in drinking water to broiler chicken vaccinated with Newcastle disease virus (NDV) vaccine. The parameters of the assessment of the immune response was the Heterophil / Lymphocyte ratio as a measure of stress, determination of the serum antibody titer post vaccination with the NDV vaccine by ELISA test and Immunohistochemical detection of macrophages by using monoclonal antibodies (mouse antichicken macrophage KUL01). A hundred and twenty (120) Chickens one day old were divided into two equal groups; group under heat stress and group control; each group was divided into two subgroups (G1, G2, G3 and G4) containing thirty chicks. The experiment was conducted for six weeks. The stressed group exposed to heat stress (≃35ºC) starting from the third week of age upto the end of the experiment. While (Group 1) and (G3) chicks were supplemented with 225µg/ml of soluble β-glucan in drinking water from day 1 to the end of the experiment, while (G2 and G4) chicks were not supplemented. The result of Heterophil /Lymphocyte ratio indicates that there was a significant (P < 0.05) difference within heat stressed treated which showed an elevated H/L ratio at 21,28 and 35 days old. Also there was a significant (P < 0.05) difference between groups that were treated with β-glucan (G1, G3) at 21, 28 and 32 days of age compared with a control non treated non stressed group (G4) at same periods. The results of antibody titer to NDV showed that there were significant (P < 0.05) differences among all groups at 7, 14 and 21 days of age, and the results of immunohistochemical analysis demonstrated positive staining for duodenal and bursal macrophages labeled with KUL-01 mouse anti-chicken monocyte- macrophages monoclonal antibodies. Tissue sections of duodenum and bursa at 14 and 24 days old stressed and non-stressed groups treated with β-glucan showed a positive result (purple-brown staining macrophages) in G1 and G3 as compared with duodenal and bursal tissues of G2 and G4groups which showed no stained cells.

Effect of supplementation of organic minerals on the performance of broilers

Effect of supplementation of organic minerals on the performance of broilers was studied on 225 coloured synthetic broiler chicks randomly divided into 5 groups. The inorganic minerals viz. Zn, Cu and Mn were added @ 40, 8 and 60 ppm, respectively in control group (T1). The inorganic minerals of treatment group were replaced with organic minerals in T2 (8 ppm organic Cu), T3 (40 ppm organic Zn) and T4 (60 ppm organic Mn) and T5/SUB> (8, 40, and 60 ppm Cu, Zn and Mn, respectively). Weekly body weight and feed consumption were recorded. At 42 day, serum biochemical indices, total ash and mineral content of tibia and carcass parameter were determined. The body weights of broiler till< third weeks of age of all the treated groups did not differ significantly. The sixth week body weight of T3 was significantly higher than that of T1. The FCR of all the treated groups did not differ significantly. The studied biochemical parameters viz. serum glucose, albumin, globulin, albumin and globulin ratio, protein, urea, calcium, phosphorus, and SGOT levels of all the treatments of the experimental broilers did not differ significantly. Significantly lower serum cholesterol and higher SGPT and ALP levels were observed in organic Zn fed groups. Carcass characteristics and tibia bone parameters of the broilers of different dietary treatments at sixth week of age did not differ significantly. From this experiment, it may be concluded that replacement of inorganic zinc with Zn-methionine resulted in better body weight of broilers.

Influence of pellet length on pellet quality and performance of broiler starters

SUMMARY An experiment was conducted to investigate the effect of pellet length on pellet quality and performance of broiler starters (7–21 d of age). A wheat-based diet was formulated and pelleted to achieve 3 desired pellet lengths (3, 5, and 7 mm). Five experimental treatments were developed by feeding broilers pellets with different lengths during the second and third weeks of age. The treatments were feeding of 3-mm (length) pellets during wk 2 and 3; feeding 3- and 5-mm pellets during wk 2 and 3, respectively; feeding 3- and 7-mm pellets during wk 2 and 3, respectively; feeding of 5-mm pellets during wk 2 and 3; and feeding 5- and 7-mm pellets during wk 2 and 3, respectively. Increasing the pellet length from 3 to 5 and 7 mm significantly improved pellet durability and hardness with a marked increase associated with increasing the pellet length from 3 to 5 mm. Over the whole trial period (d 7–21), birds fed only 3-mm pellet diets showed highest feed intake. Weight gain of birds fed 3-mm pellets through the entire experiment was similar to those fed 5- and 7-mm pellets, but higher than other dietary treatments. Overall, the physical quality of pellets can be significantly enhanced by increasing the pellet length. However, young broilers (7–14 d of age) show a preference for shorter pellets.

Prevention of arterial calcification corrects the low bone mass phenotype in MGP-deficient mice

Matrix gla protein (MGP), a potent inhibitor of extracellular matrix (ECM) mineralization, is primarily produced by vascular smooth muscle cells (VSMCs) and chondrocytes. Consistent with its expression profile, MGP deficiency in mice (Mgp−/− mice) results in extensive mineralization of all arteries and cartilaginous ECMs. Interestingly, we observed a progressive loss of body weight in Mgp−/− mice, which becomes apparent by the third week of age. Taking into account the new paradigm linking the metabolic regulators of energy metabolism and body mass to that of bone remodeling, we compared the bone volume in Mgp−/− mice to that of their wild type littermates by micro-CT and bone histomorphometry. We found a decrease of bone volume over tissue volume in Mgp−/− mice caused by an impaired osteoblast function. In culture, early differentiation of Mgp−/− primary osteoblasts was not affected; however there was a significant upregulation of the late osteogenic marker Bglap (osteocalcin). We examined whether the prevention of arterial calcification in Mgp−/− mice could correct the low bone mass phenotype. The bones of two different genetic models: Mgp−/−;SM22-Mgp and Mgp−/−;Eln+/− mice were analyzed. In the former strain, vascular calcification was fully rescued by transgenic overexpression of Mgp in the VSMCs, while in the latter, elastin haploinsufficiency significantly impeded the deposition of minerals in the arterial walls. In both models, the low mass phenotype seen in Mgp−/− mice was rescued. Our data support the hypothesis that the arterial calcification, not MGP deficiency itself, causes the low bone mass phenotype in Mgp−/− mice. Taken together, we provide evidence that arterial calcification affects bone remodeling and pave the way for further mechanistic studies to identify the pathway(s) regulating this process.

Mating behavior, egg laying, and embryonic development in the South American apple snail Asolene pulchella (Ampullariidae, Caenogastropoda)

Asolene pulchella is a dioecious freshwater snail from the La Plata basin, belonging to the Ampullariidae family. Our aim was to study the reproductive biology, including mating behavior, egg laying, and embryonic development under laboratory conditions. Copulations occurred underwater and lasted 2.66 h on average. The males produce fusiform paraspermatic cells (with seven to nine flagella) in addition to euspermatic cells with a corkscrew head, straight middle piece and long flagellum. Females stored sperm for up to 169 days. The egg masses (containing 98.1 eggs on average) are deposited underwater and are composed of many gelatinous packs of 1–4 eggs; the jelly matrix presented numerous calcite microcrystals. The spheroidal egg capsules measured 2.25 mm and contained a yellowish perivitellus of rubbery consistence. The embryonic development extends for 10.8 days on average. Hatchlings measured 1.4 mm and remained on the egg mass, feeding on the jelly. They resemble miniature adults but only began to feed on senescent plant material in their third week of age and begin aerial lung respiration after 8–10 weeks. The details of the structure of the egg masses and development constitute a rich source of traits for comparative and taxonomic studies in the Ampullariidae.

Thermal comfort temperature update for broiler chickens up to 21 days of age

Due to changes in genetics and nutrition, as well as in acclimatization of broiler chickens to the Brazilian climate, temperature values currently accepted as optimal may be outdated. The objective of this research was to update the environment temperatures that characterize the thermal comfort for broilers chickens from one to 21 days of age, under Brazilian production conditions. This research was conducted with 600 COBB birds, which were distributed in five growth chambers maintained at different temperatures during the first three weeks of age. During the experimental period, temperature values were progressively reduced, consisting in five treatments: T2724/21, T30/27/24, T33/30/27, T36/33/30 and T39/36/33. It was observed that the birds maintained in the T30(27-24) treatment presented better performance compared to other environment conditions. Based on the obtained regression models, the environment temperature values that provide greater weighing gain for the broiler chicken growth in the initial period were 31.3, 25.5 and 21.8 ºC, respectively for the first, second and third week of age.

Estimation of Optimal Lysine in Quail Chicks During the Second and Third Weeks of Age

An experiment was conducted to assess the optimal levels of dietary lysine (Lys) in Japanese quail from 7 to 21 days of age. A dose-response diet was formulated to be adequate in all amino acid concentrations with the exception of Lys. Different levels of supplemental L-Lysine.HCl were added to the dose-response diet at the expense of corn starch, sodium bicarbonate, and NaCl to create 6 levels of Lys ranged from 0.91% to 1.51% in diet. Optimal Lys for feed conversion ratio, breast meat yield, and thigh meat yield were estimated at 1.15%, 1.21%, and 1.16% of diet, respectively, based on linear broken-line regression. With quadratic broken-line regression, the Lys requirements for body weight gain, feed conversion ratio, thigh meat yield, and breast meat yield were estimated at 1.27%, 1.21%, 1.32%, and 1.34% of diet, respectively. Overall, Lys requirements of starting Japanese quail may be at least 1.34% of diet for optimizing carcass attributes fed low-CP dose-response diet.

Elucidation of colonization time and prevalence of thermophilic Campylobacter species during turkey rearing using multiplex polymerase chain reaction

Two turkey flocks (male and female) and the environment of their house were investigated for the presence of thermophilic Campylobacter. Sample DNA was extracted directly from fecal material and environmental samples. Bacterial identification was done using a modified Campylobacter species specific multiplex PCR. The times needed for colonization and prevalence in male and female turkeys were determined independently. All environmental samples collected before restocking were negative in the PCR analysis, showing a good hygiene and biosecurity system. The first positive PCR results were obtained in drinking water samples at 6 d of age. Colonization occurred between the second and third week of age, starting in female birds and then followed by the males. Campylobacter jejuni was detected by multiplex PCR at first; later on, Campylobacter coli and mixtures of both were seen. After the 9 wk of age, the colonization of the flocks was completed. Great attention should be given to drinking water as a supposed source of Campylobacter contamination. Multiplex PCR proved to be a rapid, sensitive, and cheap tool for the diagnosis of Campylobacter contamination.

PERSISTENCIA DE ANTICUERPOS MATERNALES CONTRA EL VIRUS DE LA PESTE PORCINA CLÁSICA EN LECHONES NACIDOS DE MARRANAS EN GRANJAS CON DIFERENTES ESTRATEGIAS DE VACUNACIÓN

In the study was evaluated the persistence of maternal antibodies levels against the Classical Swine Fever virus (CSFV) in piglets born from vaccinated sows from two farms (A and B) with different vaccination strategies against CSFV. In farm A sows were vaccinated at 90 days of gestation and in farm B at 18 - 21 days postpartum. Serum samples were collected from piglets of both farms, at first (n=15), third (n=15), fifth (n=15) and seventh (n=15) weeks of age, and from 15 sows from each farm A for detection of antibodies against CSFV by the indirect ELISA test. All piglets had maternal antibodies against CSFV at first week of age, persisting in most of them to the seventh week of age. Significant differences between farms were found (p<0.05) on levels of maternal antibodies in piglets at first and third week of age. Also, higher variability on antibody levels was observed n piglets and sows in farm A. The results suggest that the level and persistence of the maternal antibodies in piglets depend of vaccination strategies against PPC virus.

ADIÇÃO DE FITASE EM RAÇÕES COM DIFERENTES NÍVEIS DE ENERGIA METABOLIZÁVEL, PROTEÍNA BRUTA E FÓSFORO DISPONÍVEL PARA FRANGOS DE CORTE DE 1 A 21 DIAS

The objective of this study was to evaluate the performance and the pollutant excretion of broilers from 1 to 21 days of age fed diets with different levels of metabolizable energy (MEn), crude protein (CP) and available phosphorus (aP), supplemented with amino acids and phytase. To evaluate the performance, 1,350 Cobb broilers at one day of age (weight of 45.5 ± 0.9g) were distributed in a completely randomized design in a 4x2+1 factorial arrangement (four levels of MEn – 2,850; 2,950; 3,050 and 3,150 kcal/kg – and two of CP and aP – 17 with 0.34% and 19 with 0.25%, respectively, all with phytase, and an additional treatment – control, without phytase, with 21% PB, 3,000 kcal/kg MEn and 0.46% aP), in six replications with 25 birds. To evaluate the excretion of pollutants, 270 broilers at 14 days of age were allotted in metabolic cages in groups of five during seven days, using the same statistical design. Although the use of phytase reduced phosphorus and copper excretion, it decreased weight gain and increased feed conversion ratio in all studied nutritional plans. In phytase-diets, the energetic levels linearly reduced feed intake and improved feed conversion ratio and calcium and potassium excretion. Energy reduced the nitrogen, phosphorus and zinc excretion only in 17% CP and 0.34% aP diets. Crude protein reduction in phytase-diets improved feed conversion ratio and reduced nitrogen and potassium excretion. It was concluded that phytase decreases broiler performance until the third week of age when combined with reduced levels of CP and aP in diets. KEYWORDS: additive; enzyme; excrement quality; ideal protein; nutrition.

Effects of Strain on Performance, and Age at Slaughter and Duration of Post-chilling Aging on Meat Quality Traits of Broiler

This study was conducted to investigate the effects of strain on broiler performance, and age at slaughter and post- chilling (PC) aging time on meat quality traits. A total of 500 one-day-old chicks (250 Hubbard classic and 250 Lohman) were reared under commercial conditions. Half of the broiler birds from each strain were slaughtered at 32 days and the other half at 42 days old. At each processing day, 168 carcasses were randomly selected (84 Hubbard and 84 Lohman) and divided into groups of 28 carcasses within each strain, and aged for 0, 4 and 24 h after chilling. Average weekly body weight was comparable between strains. Feed conversion ratio was higher (p<0.05) for the Hubbard strain during the second and third week of age. Initial carcass pH was significantly (p<0.05) affected by age where younger birds (32-d-old) had lower pH values than older (41-d-old) birds. Breast temperature was higher (p<0.001) for Lohman than Hubbard at 0, 2 and 4 h of PC. Younger birds had a lower breast temperature (p<0.001) at all measured times of PC. Thaw loss, cook loss and water holding capacity were not significantly affected by strain, age or aging time. Lohman strain had more tender meat (p<0.05) than Hubbard strain, and tenderness was improved with the increase of broiler age and aging time. Meats from Hubbard were lighter and less red than those from Lohman strain where younger birds had darker color. In conclusion, strain, age at slaughter and PC aging duration are critical to breast meat quality characteristics, and 4 h of aging are required before deboning in order to obtain more tender fillets. (Key Words : Broiler Breast Fillets, Age at Slaughter, Strain, Aging Time, Meat Quality)

Low-frequency stimulation enhances burst activity in cortical cultures during development

The intact brain is continuously targeted by a wealth of stimuli with distinct spatio-temporal patterns which modify, since the very beginning of development, the activity and the connectivity of neuronal networks. In this paper, we used dissociated neuronal cultures coupled to microelectrode arrays (MEAs) to study the response of cortical neuron assemblies to low-frequency stimuli constantly delivered over weeks in vitro. We monitored the spontaneous activity of the cultures before and after the stimulation sessions, as well as their evoked response to the stimulus. During in vitro development, the vast majority of the cultures responded to the stimulation by significantly increasing the bursting activity and a widespread stabilization of electrical activity was observed after the third week of age. A similar trend was present between the spontaneous activity of the networks observed over 30 min after the stimulus and the responses evoked by the stimulus itself, although no significant differences in spontaneous activity were detected between stimulated and non-stimulated cultures belonging to the same preparations. The data indicate that the stimulation had a delayed effect modulating responsiveness capability of the network without directly affecting its intrinsic in vitro development.

Prevalence, prediction and risk factors of enteropathogens in normal and non-normal faeces of young Dutch dairy calves

Between January and April 2007, 424 calves under 22 days of age from 108 Dutch dairy herds were sampled to estimate the prevalence of non-normal faeces (‘custard-like’—yellowish-coloured with custard consistency or diarrhoea: watery-like faeces) and the shedding of enteropathogens Escherichia coli K99 ( E. coli), Coronavirus, Cryptosporidium parvum ( C. parvum), Rotavirus and Clostridium perfringens ( Cl. perfringens). In addition, information was collected on animal characteristics and herd-management practices. The probability of detecting each one of five enteropathogens given a calf with ‘custard-like’ faeces or diarrhoea was estimated using Bayes’ rule and was based on the predicted probabilities from a multinominal model including each of five enteropathogens as independent variables. In addition, putative risk factors for the presence of each of five enteropathogens were analysed using logistic regression models with random herd effects. Fifty-seven percent of calves had faeces of normal colour (brownish) and consistency (firm), 23.8% (95%CI: 19.8–28.2%) had ‘custard-like’ faeces and 19.1% (95%CI: 15.5–23.2%) had diarrhoea. E. coli was the least detected enteropathogen (2.6% (95%CI: 1.3–4.6%) of calves, 9% (95%CI: 5–16%) of herds) and Cl. perfringens was most detected (54.0% (95%CI: 49.1–58.8%) of calves, 85% (95%CI: 77–91%) of herds). E. coli and Coronavirus were detected incidentally in only one or two calves per herd, whereas C. parvum and Cl. perfringens were frequently detected in up to four calves per herd. For calves with ‘custard-like’ faeces, the probability of detecting Rotavirus from a calf in its first week of age was 0.31 whereas for a calf in its second week, there was a 0.66 probability of detecting C. parvum. The probabilities of detecting E. coli, Rotavirus and C. parvum in calves with diarrhoea in their first week of age were 0.10, 0.20 and 0.43, respectively. In calves with diarrhoea between 1 and 2 weeks of age, the probability of detecting enteropathogens was 0.43 for C. parvum. None of the tested enteropathogens were related to ‘custard-like’ faeces or diarrhoea in the third week of age. Putative risk factors for E. coli, Coronavirus and C. parvum included the presence of peer-calves shedding Coronavirus, C. parvum or Rotavirus, respectively. Additionally, managerial risk factors such as non-optimal hygienic housing (for Coronavirus) and the routine use of antibiotics for diarrhoeic calves (for C. parvum) were found. No animal or managerial factors were associated with shedding of Cl. perfringens.

Effect of Varying Ratios of Dietary Calcium and Phosphorus on Performance, Phytate P and Mineral Retention in Japanese Quail (Coturnix cotnurnix Japonica)

The effect of different ratios of dietary calcium (Ca) to total phosphorus (tP) on the performances and retention of minerals and phytate phosphorus (pP) by quails were studied using 600 unsexed broiler quails from 1 to 21 days of age. Treatments consist of five corn and soybean meal (CSM) based diets with variable ratios of Ca:tP (1.96, 1.81, 1.66, 1.53 and 1.39) with four replicate of 30 birds each. Diets contained 3g chromium oxide (Cr O )/kg as marker. All ratios of Ca and P had no significant effect on feed consumption 2 3 of birds. There were pronounced differences (P < 0.05) in body weight gain of chicks among treatments at second and third week of age. Improved (P < 0.05) feed conversion ratio was observed at 3 wk of age. Higher ratios of Ca:tP (1.96 and 1.81) increased (P < 0.05) the retention of P compared to other treatments while ratio of 1.96 decreased (P < 0.05) the retention of Ca and phytate. In conclusion, Ca:tP ratio of 1.81 showed positive effect on most of parameters measured in this study.

A preliminary study on the effect of employing bile liquid in a starter diet on performance of young heavy breed chicks

Heavy breed day-old chicks fed Isonitrogenous-Isocaloric diets supplemented with 0.0, 2.0 and 4.0% fresh bovine bile liquid, for three weeks. The three types of diets comprised the experimental dietary treatments, from which the effect of including bile liquid in heavy breed chicks diet on their most prominent economical traits were studied. Results showed that the three groups of birds, consumed almost the same amount of feed during the three weeks of experimental period. However, a significant increase in daily growth rate(DGR)occurred as a result of bile liquid in starter diets. The estimated superiority of this traits, DGR, was found to be 10.76% on an average basis, higher than that of the control group. A good reflection of this phenomenon on feed conversion ratio was observed, as birds fed diets contained 2.0 and 4.0% bile liquid surpassed the control group by 8.75 and 10.63%, respectively. Body weights at third week of age were 8.06 and 10.60% heavier for the two treated groups, respectively, than the control one. Results indicate that the nutritive value of starter diets supplemented with bile liquid warrant further investigation based on long term experiments to make a decision in this direction.

Optimising dietary energy and amino acid levels in the diets of naked neck broilers for growth, nutrient utilisation and immune response in a hot climate

AbstractThe need for a critical amino acid (AA) profile for growth, immune response and N utilisation of naked neck broilers during summer was studied. Day‐old naked neck chicks (n = 198) from a single hatch were distributed into 24 groups (four dietary regimens (DRs) with six replicates each) having eight birds in each replicate. The first diet was based on crude protein (CP) and metabolisable energy (ME) (13.40 MJ) as per NRC recommendations (DR1). In the second diet, the CP content was reduced through supplementation of synthetic AAs to achieve critical AA contents as suggested by NRC with 13.40 MJ ME (DR2). In the third diet critical AAs were supplemented to achieve their level at 108% of NRC with 12.6 MJ ME (DR3), while in fourth diet critical AA concentration was reduced to 94% (DR4) of NRC with 12.6 MJ ME to match the ratio of ME to AA concentration as that of NRC (1994). Diets were formulated separately for starter (0–3 weeks) and finisher (3‐6 weeks) phases. A metabolism trial was conducted at the third week of age. At 3 and 6 weeks of age eight birds (four of each sex) per treatment were killed to study the growth of immune organs (Bursa of Fabricius, thymus and spleen). Immune response was studied at the fourth week of age. During the starting phase, the birds fed DR1 and DR2 having 13.40 MJ ME kg−1 diet had higher body weight (P &lt; 0.044) gain (P &lt; 0.048) and better feed conversion ratio (FCR) (P &lt; 0.001) as compared to DR3 and DR4 (12.6 MJ ME kg−1 diets). However, better (P &lt; 0.001) CP efficiency (CP intake kg−1 gain) and lower feed cost kg−1 gain (P &lt; 0.001) was recorded in DR4. A similar trend was also observed during the finisher phase. Dietary regimens had no effect on dry matter (DM) metabolisability, N intake or output and N retention. There was no difference in the weight of immune organs (bursa, thymus and spleen) between dietary treatments at either 3 or 6 weeks of age. The cell mediated and humoral immune response was also not different between the NRC and modified NRC levels. Copyright © 2007 Society of Chemical Industry

Urinary F2-isoprostanes are poor prognostic indicators for the development of bronchopulmonary dysplasia

Oxygen toxicity is thought to contribute to the development of bronchopulmonary dysplasia (BPD). Oxidant injury leads to formation of F(2)-isoprostanes (F(2)-IsoP). We hypothesized that urinary excretion of the stable metabolite of F(2)-IsoP, 8-iso-PGF(2alpha), would be higher in infants who develop BPD than those who did not. Forty infants <30-weeks gestational age (GA) were enrolled, 24 infants with BPD and 16 without BPD. Urine specimens were collected weekly and stored at -80 degrees C until analyzed. Urinary 8-iso-PGF(2alpha) was measured by gas chromatography/mass spectrometry (GC-MS) and normalized to creatinine excretion. GA and birth weight (BW) were lower in infants who developed BPD than those who did not. Urinary 8-iso-PGF(2alpha) levels in the first or third weeks of age were not significantly different between the two groups. Urinary excretion of 8-iso-PGF(2alpha) in early postnatal life in preterm infants is not correlated with the development of BPD.

Response of growing Japanese quails to dietary concentration of L‐threonine

AbstractThe influence of dietary levels of L‐threonine (Thr) on growth and immune response was investigated in growing (0–5 weeks of age) Japanese quails (n = 288). Three dietary treatments were formulated using three levels of Thr [9.6, 10.2 and 11.2 kg−1 diet dry matter (DM)] at a fixed protein level of 233 g kg−1 and an energy level of 12.15 MJ (2900 kcal) metabolizable energy (ME) kg−1 feed dry matter. A metabolism trial with a 3‐day collection period was conducted at the third week of age employing all the birds. The cell‐mediated (using PHA‐P) and humoral (SRBC response) immune responses were measured at the fourth week of age. Carcass traits were assessed at the end of fifth week of age. Body weight gain was lower (P &lt; 0.01) in birds received 9.6 g Thr kg−1 DM than in groups fed 10.2 g or 11.2 g kg−1 DM in the diet, but there was no significant difference in gain between the groups fed 10.2 or 11.2 g Thr kg−1 DM in the diet. Feed intake differed significantly owing to Thr levels being lowest (P &lt; 0.05) at 9.6 g Thr kg−1 DM in the diet. Feed conversion ratio (FCR), protein efficiency and energy efficiency improved at the 11.2 g kg−1 level from 0 to 3 weeks of age; however, from 3 to 5 weeks of age, better FCR emanated from a diet with 9.6 g Thr kg−1 DM. The nitrogen balance did not differ (P &gt; 0.05) with Thr level. Carcass traits, relative weight of immune organs and cell‐mediated (PHA‐P) and humoral (SRBC response) immune responses did not differ significantly (P &gt; 0.05) as a result of the dietary treatments. Copyright © 2006 Society of Chemical Industry