Week-old Broiler Research Articles

Week-Old Chicks with High Bacteroides Abundance Have Increased Short-Chain Fatty Acids and Reduced Markers of Gut Inflammation.

As important commensals in the chicken intestine, Bacteroides are essential complex carbohydrate degraders, and short-chain fatty acid (SCFA) producers that are highly adapted to the distal gut. Previous studies have shown large variation in Bacteroides abundance in young chickens. However, limited information is available regarding how this variation affects the gut microbiome and host immunity. To investigate how elevated or depleted Bacteroides levels affect gut microbial functional capacity and impact host response, we sampled 7-day-old broiler chickens from 14 commercial production flocks. Week-old broiler chickens were screened and birds with low Bacteroides (LB) and high Bacteroides (HB) abundance were identified via 16S rRNA gene amplicon sequencing and quantitative PCR (qPCR) assays. Cecal microbial functionality and SCFA concentration of chickens with distinct cecal Bacteroides abundance were profiled by shotgun metagenomic sequencing and gas chromatography, respectively. The intestinal immune responses of LB and HB chickens were assessed via reverse transcription qPCR. Results showed that the gut microbiota of the LB group had increased abundance of lactic acid bacteria pyruvate fermentation pathway, whereas complex polysaccharide degradation and SCFA production pathways were enriched in the HB group (P < 0.05), which was supported by increased SCFA concentrations in the ceca of HB chickens (P < 0.05). HB chickens also showed decreased expression of interleukin-1β and increased expression of interleukin-10 and tight-junction protein claudin-1 (P < 0.05). Overall, the results indicated that elevated Bacteroides may benefit the 7-day broiler gut and that further work should be done to confirm the causal role of Bacteroides in the observed positive outcomes. IMPORTANCE To date, limited information is available comparing distinct Bacteroides compositions in the chicken gut microbial communities, particularly in the context of microbial functional capacities and host responses. This study showed that possessing a microbiome with elevated Bacteroides in early life may confer beneficial effects to the chicken host, particularly in improving SCFA production and gut health. This study is among the first metagenomic studies focusing on the early life chicken gut microbiota structure, microbial functionality, and host immune responses. We believe that it will offer insights to future studies on broiler gut microbial population and their effects on host health.

Study of the effect of ultrafine particles of copper and iron on mineral metabolism in the body of broiler chickens on a semisynthetic diet

Relevance.Today, the livestock industry is facing a serious problem associated with unbalanced nutrition of farm animals, which does not allow to fully realize the full potential of the industry. In this regard, it is necessary to conduct research aimed at finding a solution to this problem and developing ways to provide animals with good nutrition. The aim of this study was to study the effect of ultrafine particles (UFP) of copper and iron on mineral metabolism and microbial diversity of the caecum of broiler chickens on a semi-synthetic diet.Methods.Experimental studies to assess the effect of ultrafine particles of copper and iron on the metabolism of broiler chickens of the Arbor Acres cross, which are on a semi-synthetic diet, were carried out on 120 week-old broiler chickens, which were divided into 4 groups (n = 30) by the method of pairs of analogues. The birds received a semi-synthetic diet (SR) and a semi-synthetic diet deficient in trace elements in our modification (SDR). The I experimental group received UFP Cu at a dosage of 2.5 mg/kg of feed, and the II experimental group received UFP Fe at a dosage of 2.5 mg/kg of feed.Results.Absorption and metabolism of ultrafine parts of copper and iron in the body of a bird depend on the physico-chemical properties, such as size, shape and method of administration, as well as the dose of ultrafine particles of copper and iron. Therefore, the present results are an important indication of the potential for using UHF as an effective source of Cu and Fe for broilers.

Growth performance and haematological characteristics of broiler finisher chickens fed palm kernel cake as partial replacement for maize and Soya bean

High feed cost resulting from the use of conventional feed ingredients represents a major challenge in broiler production in South-East Nigeria. Feed constitutes 70% of the cost of production of broiler chickens hence, the replacement of unconventional feed ingredients holds the key to sustainable poultry production. This trial was aimed at determining the optimum inclusion level of palm kernel cake as a partial replacement of soya bean and maize in a broiler finisher diet during a 28-day trial. The PKC was included at 0%, 35%, 40% and 45% of total feed composition and birds were fed ad libitum. A total of one hundred and twenty (120) four week-old broilers were used for the measurements. Birds were allotted to four treatment groups of 10 birds each with three replications in a completely randomized design (CRD). The growth performance and haematological characteristics were evaluated. The results showed significant differences (P&lt;0.05) in the final weight gains, average weight gain and feed conversion ratio but no significant differences was observed in the feed intake. The control diet had the highest average weight gain of 919.20g and 40% PKC inclusion had the least value of 595.47g. At end of the experiment, 6 birds randomly selected from each treatment were fasted overnight and slaughtered for blood samples collection. The results of the haematological parameters indicated significant differences (P&lt;0.05) in the haemoglobin (Hb) concentrations, packed cell volume (PCV), total white blood cell counts (WBC), respectively. Furthermore, the mean cell volume (MCV), mean cell heamoglobin (MCH), mean cell heamoglobin concentration (MCHC) all showed significant variation. However, no significant differences were observed in the red blood cell count (RBC). From this study, it could be concluded that although broiler birds can tolerate high inclusion levels of PKC up to 40%, 35% was the level of inclusion that would result to higher weight gains for optimum productivity.

Eggshell Water Vapor Conductance and Shell Structural Characteristics of Broiler Breeder in Different Flock Ages

The aim of the study was to investigate eggshell traits; including eggshell water vapor conductance, eggshell thickness, pore density, egg weight loss as well as eggshell surface area and volume in 28 and 40 week-old broiler breeders. Furthermore, the phenotypic correlations among the eggshell characteristics were determined. The eggs were ranged from 54.41 g to 60.78 g and 54.71 g to 60.62 g in 28 and 40 wk-old age groups, respectively. All eggs were weighed and numbered before setting and were monitored individually until the end of the incubation. Mean eggshell water vapor conductance (G) value was 11.00±1.01 mg H2O day-1 torr-1 in 28 wk-old flock and 11.99±1.28 mg H2O day-1 torr-1 in 40 wk-old flock respectively (P<0.05). The mean value of shell thickness and pore density mean along with the two regions (broad end and equator) were higher and significant in 28 wk-old flock (P<0.01). Egg weight loss was not found to be significant. Surface area was higher in 40 wk-old flock while as volume was higher in 28 wk-old flocks (P<0.01). There was no correlation between eggshell thickness and pore density. Both eggshell thickness and pore density were having significant positive correlation along with three eggshell regions in each flock ages (P<0.01).

Age-Related P-Glycoprotein Expression in the Intestine and Affecting the Pharmacokinetics of Orally Administered Enrofloxacin in Broilers

Bioavailability is the most important factor for the efficacy of any drug and it is determined by P- glycoprotein (P-gp) expression. Confirmation of P-gp expression during ontogeny is needed for understanding the differences in therapeutic efficacy of any drug in juvenile and adult animals. In this study, Abcb1 mRNA levels in the liver and intestine of broilers during ontogeny were analysed by RT qPCR. Cellular distribution of P-gp was detected by immunohistochemstry. Age-related differences of enrofloxacin pharmacokinetics were also studied. It was found that broilers aged 4 week-old expressed significantly (P<0.01) higher levels of P-gp mRNA in the liver, jejunum and ileum, than at other ages. However, there was no significant (P>0.05) age-related difference in the duodenum. Furthermore, the highest and lowest levels of Abcb1 mRNA expression were observed in the jejunum, and duodenum, respectively. P-gp immunoreactivity was detected on the apical surface of the enterocytes and in the bile canalicular membranes of the hepatocytes. Pharmacokinetic analysis revealed that the 8 week-old broilers, when orally administrated enrofloxacin, exhibited significantly higher Cmax (1.97 vs. 0.98 μg•ml-1, P=0.009), AUC(14.54 vs. 9.35 μg•ml-1•h, P=0.005) and Ka (1.38 vs. 0.43 h-1, P=0.032), as well as lower Tpeak (1.78 vs. 3.28 h, P=0.048) and T1/2ka (0.6 vs. 1.64 h, P=0.012) than the 4 week-old broilers. The bioavailability of enrofloxacin in 8 week-old broilers was increased by 15.9%, compared with that in 4 week-old birds. Interestingly, combining verapamil, a P-gp modulator, significantly improved pharmacokinetic behaviour of enrofloxacin in all birds. The results indicate juvenile broilers had a higher expression of P-gp in the intestine, affecting the pharmacokinetics and reducing the bioavailability of oral enrofloxacin in broilers. On the basis of our results, it is recommended that alternative dose regimes are necessary for different ages of broilers for effective therapy.

Tannia (Xanthosoma sagittifolium) Cocoyam As Dietary Substitute For Maize in Broiler Chicken.

The effects of feeding varying levels of tannia Cocoyam Meals (CCYM) as substitutes for maize were evaluated on 96, four week-old broiler chicken. The diets included raw sundried and boiled sundried tannia. Each form replaced maize at 0, 25, 50 and 100% level. The differences in weight gain, feed intake and feed conservation ratio were not significant (P> 0.05) up to 50% substitution level for both cocoyam diets . The control only differed from cocoyam diets at 100% substitution indicating that raw sundried and boiled tannia CCYM has good potentials in feeding value up to 50% inclusion levels. Feed cost and cost of daily feed intake significantly decrease (P<0.05) with increase in the level of CCYM inclusion in boiled and raw sundried tannia respectively. The level of anti-nutritional factors (phytate, oxalate, tannin and saponin) differed significantly (P< 0.01) between the raw sundried tannia (1.29, 33.32, 1.52, 6.40) and boiled tannia (0.15, 21.70, 0.14, 4.30). Thus, much better performance observed on groups fed diets with boiled cocoyam. Possibly due to heat treatment effects which destroyed the anti-nutritional factors. Therefore, with proper processing CCYM could effectively replaced maize at 50% inclusion level in finishing diets of broilers.

Influence of dietary copper and vitamin A on immune function of broilers

采用4×2(铜×维生素A)完全随机试验设计, 研究了日粮添加不同水平的铜(0 mg·kg^-1、8 mg·kg^-1、150 mg·kg^-1、225 mg·kg^-1)和维生素A(1 500 IU·kg^-1、5 000 IU·kg^-1)对肉仔鸡不同生长阶段(0~4 周龄和5~7 周龄)免疫功能的影响。结果表明: 添加铜为8 mg·kg^-1 时, 肉鸡生长前期(0~4 周龄)可显著(<em>P</em><0.05)或极显著(<em>P</em><0.01)提高肉鸡脾脏活化T 淋巴细胞百分率和血清抗体效价, 生长后期(5~7 周龄)可极显著(<em>P</em><0.01)或显著(<em>P</em><0.05)提高脾脏、胸腺、盲肠扁桃体活化T 淋巴细胞百分率和外周血液中活化T、B 淋巴细胞百分率; 整个试验期添加高铜(150 mg·kg^-1、225 mg·kg^-1)时, 活化T、B 淋巴细胞百分率均不同程度下降。添加维生素A 5 000 IU·kg^-1 时, 肉鸡生长前期可显著(<em>P</em><0.05)提高其外周血液中活化T 淋巴细胞百分率, 生长后期可极显著(<em>P</em><0.01)或显著(<em>P</em><0.05)提高脾脏、盲肠扁桃体活化T 淋巴细胞百分率和血清抗体效价。铜和维生素A 互作效应对肉鸡生长前期的活化T、B 淋巴细胞百分率和血清抗体效价影响不显著, 对生长后期的外周血液、胸腺、盲肠扁桃体活化T 淋巴细胞百分率影响显著(<em>P</em><0.05), 以8 mg·kg^-1 铜× 5 000 IU·kg^-1 维生素A 处理最高; 以上结果提示铜和维生素A 对肉鸡免疫功能的影响存在互作效应。

국내에서 분리한 Ornithobacterium rhinotracheale 균의 종란과 육계에서의 병원성

본 시험은 국내에서 분리한 Ornithobacterium rhinotracheale(OR) 병원성 세균이 부화중인 종란과 일반 육계에서 얼마만큼 병원성을 보이는지 알아보기 위하여 수행하였다. 첫 번째 9일령 부화란의 yolk sac에 국내에서 분리한 3종의 OR strain을 접종하여 12일동안 관찰한 결과, 66% 이상의 폐사율이 관찰되어 높은 병원성이 인정되었다. 두 번째로 3주령 일반 육계를 대상으로 5가지 다른 공격접종법[Intratracheal, Intravenous, Intramuscular, Aerosol, Newcastle Disease Virus(NDV)와 혼합 Aerosol]으로 접종한 다음 병원성을 관찰하였다. NDV와 OR균을 동시에 분무 접종한 계군에서만 특이적인 임상증상인 침울, 기침, 안면 종대와 함께 부검시 치즈양 또는 요구르트와 비슷한 염증성 삼출물이 기낭에 관찰되었다. 조직학적으로도 기낭상피세포의 변성과 탈락, 대식세포와 다형태성 관립구의 침윤, 부종 등의 기낭염이 확인되었으며, 이들 기낭을 이용한 면역 조직 화학적 염색법을 적용한 결과 다량의 OR균의 항원이 검출되었다. 그러나 OR균만 단독 처리한 닭에서는 일시적이고 경미한 조직학적 병변만이 관찰되었다. 결론적으로 NDV가 OR균의 감염에 따른 임상 증상과 병리조직학적 병변 유발에 주요한 역할을 하는 것으로 판단된다. Field strains of Ornithobacterium rhinotracheale (OR) were tested on their virulence in specific pathogen free (SPF) embryonated chicken eggs and 3-week-old broilers. When infected with three different OR isolates (OR-161, OR-240 and OR-295) through yolk sac infection route, all strains appeared to be highly pathogenic with responsible mortality 66% and 100% within 12 days post infection (DPI). To test the virulence of OR in the commercial broilers, 3 week-old broilers were grouped depends on the inoculation route of OR isolate (OR-295) through five different infection routes; group 1 (IT: intratracheal), group 2 (IM: intramuscular), group 3 (IV: intravenous), group 4 (aerosol) and group 5 [Mixed: NDV (LaSota)+OR aerosol]. Within 5 to 7 days after inoculation, only broilers given NDV+OR were slightly depressed and coughing, and had mild facial redness. Grossly, foamy and yellow-white yogurt like exudate in the air sacs, predominantly in the abdominal air sacs was present. In histology, infiltration of the air sac epithelium and lamina propria by macrophage and polymorphonuclear granulocytes was seen with cell debris and inflammatory cells, correlated with the presence of OR antigen, as demonstrated by immunohistochemistry. Field strains of OR were able to induce high mortality in the embryonated chicken eggs, whereas broilers were less susceptible to OR infection. Interestingly, in the absence of NDV infection, the four groups of OR single infection only different route showed minimal and temporary microscopic air sac lesions. Thus, Newcastle disease virus (LaSota strain) showed triggering effects on the OR infection in chickens.

Thiram-Induced Changes in the Expression of Genes Relating to Vascularization and Tibial Dyschondroplasia

Tibial dyschondroplasia (TD), a major metabolic cartilage disease in poultry, is characterized by the distension of proximal growth plates of tibia that fail to form bone, lack blood vessels, and contain nonviable cells. Thiram, a carbamate pesticide, when fed to young broiler chicks induces TD with high regularity and precision. We used this experimental model to understand the cause of the defects associated with TD by determining the expression of selective candidate genes associated with vascularization and cell survival. Week-old broiler chickens were fed 100 ppm thiram for 48 h between d 8 and 10 posthatch and the expression of the genes for vascular endothelial growth factor (VEGF), its receptors (VEGFR1 and VEGFR2), and an antiapoptotic protein (Bcl-2) were determined in the growth plate cartilage at 48 and 166 h after feeding thiram. Reverse transcription PCR and capillary electrophoresis were used to determine the expression of these genes relative to the 18S gene as an internal standard. There was an increase in the expression of the VEGF gene by thiram at 48 h, which remained elevated above the control level at 166 h. A suppression of genes encoding both VEGF receptors and Bcl-2 was evident at 48 h in thiram-fed chickens when there was no visible distension of growth plate indicative of TD. At 166 h, however, there was a significant distension of growth plates in thiram-treated birds, with a high percentage of cells derived from these tissues exhibiting characteristics of dead cells. Although the expressions of VEGF receptors were low at 166 h in thiram-treated birds, they were not statistically different from controls; the Bcl-2 gene expression, however, remained significantly downregulated in those birds. It appears that some of the early effects of thiram on the growth plate may be the failure of genes encoding VEGF receptors and Bcl-2 resulting from endothelial cell death, which compromise vascularization, cartilage remodeling, and the removal of dead chondrocytes leading to TD lesions.

Risk factors and likelihood of Campylobacter colonization in broiler flocks

Campylobacter was investigated in cecal droppings, feces, and cloacal swabs of 22 flocks of 3 to 5 week-old broilers. Risk factors and the likelihood of the presence of this agent in these flocks were determined. Management practices, such as cleaning and disinfection, feeding, drinkers, and litter treatments, were assessed. Results were evaluated using Odds Ratio (OR) test, and their significance was tested by Fisher’s test (p<0.05). A Campylobacter prevalence of 81.8% was found in the broiler flocks (18/22), and within positive flocks, it varied between 85 and 100%. Campylobacter incidence among sample types was homogenous, being 81.8% in cecal droppings, 80.9% in feces, and 80.4% in cloacal swabs (230). Flocks fed by automatic feeding systems presented higher incidence of Campylobacter as compared to those fed by tube feeders. Litter was reused in 63.6% of the farm, and, despite the lack of statistical significance, there was higher likelihood of Campylobacter incidence when litter was reused. Foot bath was not used in 45.5% of the flocks, whereas the use of foot bath associated to deficient lime management increased the number of positive flocks, although with no statiscal significance. The evaluated parameters were not significantly associated with Campylobacter colonization in the assessed broiler flocks.

Induction of Tibial Dyschondroplasia by Carbamate and Thiocarbamate Pesticides

Tibial dyschondroplasia (TD) is a major poultry leg problem, the natural etiology of which is unknown. Certain dithiocarbamate pesticides such as tetramethyl thiuram disulfide (thiram) have been shown to induce the disease in chickens. Because many different carbamate and thiocarbamate chemicals are used in a number of agricultural, industrial, and household applications, the objective of this study was to determine whether all chemicals of these categories induce TD and whether there is a concentration-dependent relationship between the ingestion of these chemicals and the incidences and the severity of the disease. Week-old broiler chicks were fed diets containing thiram or other assorted carbamate and thiocarbamate pesticides mixed in feed for 24-48 hr between ages 8 and 10 days. The birds were killed on day 15 and the proximal tibial and tarsometatarsal growth plates were evaluated for the presence and severity of TD lesions. TD was distinguished by broadening of growth plates; upon histologic exam chondrocytes appeared to be shrunken and dead. When compared by including equimolar concentrations of these chemicals in the feed, the dithiocarbamates with more than two sulfide groups, such as disulfiram, ferbam, thiram, and ziram were potent inducers of TD, whereas those with two sulfides to no sulfide group appeared ineffective at inducing TD. Both thiram and ferbam also reduced the bird's body weights. Thiram increased the incidence and the severity of the disease, denoted by TD index, in a dose-dependent manner. These results suggest that inadvertent contamination of feed or litter with some of these or similar chemicals may cause leg problems in poultry.

EFEITO DA IDADE DA MATRIZ NO TEMPO DE ECLOSÃO, TEMPO DE PERMANÊNCIA DO NEONATO NO NASCEDOURO E O PESO DO PINTAINHO

Utilizaram-se 600 ovos embrionados, provenientes de matrizes de 32, 43 e 60 semanas de idade, da linhagem Cobb – 500, incubados a 37,8°C e 60% de umidade. Foram analisados peso do ovo, peso dos ovos aos 19 dias de incubação, tempo de incubação, perda de peso do ovo durante a incubação, peso dos pintainhos no momento do nascimento e na retirada do nascedouro e perda de peso do pintainho no nascedouro. Foi utilizado um delineamento inteiramente ao acaso com 3 tratamentos (idade da matriz) e 200 repetições (cada ovo foi considerado uma repetição). Os resultados foram submetidos à análise de variância e Teste de Tukey (5%). Matrizes mais velhas produziram ovos mais pesados. Não houve diferença na perda de peso de ovos, no percentual de peso dos pintainhos, no tempo de incubação (h) e também na perda de peso do pintainho no nascedouro. Houve uma correlação positiva (0,75; 0,86; 0,79 respectivamente para matrizes de 32, 43 e 60 semanas) entre o peso inicial dos ovos e o peso dos ovos aos 19 dias de incubação, com o peso do pintainho, no momento do nascimento (0,57; 0,72; 0,72) e no momento da retirada do nascedouro (0,38; 0,41; 0,51). Também houve correlação (0,61; 0,41 e 0,63) entre o tempo de incubação e o peso do pintainho e com a perda de peso do pintainho no nascedouro (-0,79; -0,96; -0,76). Conclui-se que a idade da reprodutora afeta o peso do ovo e do pintainho. Ovos de matrizes de diferentes idades necessitam o mesmo tempo para incubação.

Is sequential feeding a suitable technique to compensate for the negative effects of a tropical climate in finishing broilers?

Feed withdrawal during the warmest part of the day (09:00 to 16:00 h) was compared with the distribution of ground corn and commercial feed consumed ad libitum by control broilers from 28 to 42 d exposed to tropical climatic conditions (averaged Ta = 25 °C; Relative Humidity (RH) = 72%). From 16:00 to 09:00 h, a continuous illumination was in the poultry shed and the chickens received a commercial diet. Each diet was supplied to 7 pens of 14 unsexed broilers. Both feed withdrawal and corn distribution during the day period reduced growth (P < 0.01) and deteriorated feed conversion (P < 0.01) compared to the ad libitum control. At the age of 41 d, the average body temperature (Tb) at 14:00 h in the control group was 42.56 °C. It was higher (P < 0.002) than that recorded in the corn fed group (42.27 °C) and the feed withdrawal chickens (42.11 °C). These effects measured in 4-6 week-old broilers exposed to a moderate tropical climate, illustrate the limitation of feed restriction and sequential feeding under practical conditions. Further research is needed to study the diurnal distribution of corn or feed withdrawal coupled with a balanced diet richer in essential amino acids than the commercial diet during the nocturnal period.

Role of cochlear integrity in cochlear nucleus glucose metabolism and neuron number after cochlea removal in aging broiler chickens

In the chicken auditory system, cochlear nucleus (nucleus magnocellularis, NM) neurons receive their only excitatory input from the ipsilateral cochlea. Cochlea removal (CR) results in an immediate decrease in NM neuron electrical activity, followed by death of ∼30% of NM neurons. Previous work showed a decrease in NM activity and subsequent loss of NM neurons in all chicks. Egg layer adults showed NM neuron loss after CR, while neuron number remained stable in broiler adults. This suggested that effects of CR on NM were age- and breed-dependent. We now know that most aging egg layer chickens maintain largely normal cochleae throughout adulthood. Some exhibit cochlear damage with age. The converse is true of broiler chickens. Most aging broiler chickens display cochlear degeneration, with some maintaining normal cochlear anatomy throughout adulthood. The presence of extensive cochlear damage may alter the effect of CR on NM, leading to the described differences. Here, we examine the effect of unilateral CR on NM glucose metabolism and neuron number in 2, 30, 39, and 52 week-old broiler chickens found to have normal cochleae. Chickens with damaged cochleae were excluded. Using 2-deoxyglucose uptake to evaluate bilateral NM glucose metabolism, we found significantly decreased uptake ipsilateral to CR at each age examined. Bilateral cell counts revealed significant neuron loss ipsilateral to CR at each age examined. This suggests that NM glucose metabolism decreases and subsequent neuron death occurs in aging broiler chickens when a normal cochlea is removed. The status of the cochlea must play a role in the effect of deafferentation on NM glucose metabolism and neuron survival. The effect of CR appears to be dependent upon neither age nor breed, but upon cochlear integrity instead.

Effect of broiler breeder age on pancreas enzymes activity and digestive tract weight of embryos and chicks

A study was carried out to evaluate the effect of broiler breeder age on the development of the digestive tract of embryos and chicks. Fertilized eggs Cobb from 30 and 60 week-old broiler breeder was utilized in this experiment. The results showed that eggs from older (60 weeks of age) broiler breeders were heavier (p = 0.001) than those from younger (30 weeks of age) broiler breeder. In addition, older broiler breeder had larger (p = 0.001) embryos showing a higher yolk sac (p = 0.001) and higher gastrointestinal tract relative weight (p = 0.007) than those from younger broiler breeder. The activities of pancreatic lipase and trypsin enzymes were also higher in embryos from older broiler breeder than those from younger broiler breeder (p = 0.001 and p = 0.002, respectively). Nevertheless, at the seven-day-old chick, no difference was observed in relative weight of gastrointestinal tract or pancreatic lipase and trypsin activities between older and younger broiler breeder age. However chicks from older broiler breeder were heavier than those from younger broiler breeder (p = 0.005). These data suggest that broiler breeder age is important on grower and on the development of the gastrointestinal tract and pancreatic lipase and trypsin activities of embryo. However after one week of hatching the morphophysiological difference disappear.

Desenvolvimento do Trato Gastrointestinal de Embriões Oriundos de Matrizes Pesadas de 30 e 60 Semanas de Idade

O objetivo deste trabalho foi investigar o efeito da idade das matrizes pesadas sobre o desenvolvimento do trato gastrointestinal (TGI) dos embriões no terço final do período de incubação, bem como a utilização das reservas do saco vitelino nas 24 h pós-eclosão, em pintos alimentados ou em jejum. Foram utilizados ovos férteis da linhagem Cobb 500, oriundos de matrizes pesadas com 30 e 60 semanas de idade. O desenvolvimento do TGI (proventrículo+moela, segmentos do intestino delgado e saco vitelino) foi estudado entre o 17º e 21º dias de incubação (Experimento 1). Nas 24 h pós-eclosão foi pesquisado o efeito da presença ou não de alimento no lúmen intestinal sobre a utilização das reservas do saco vitelino (Experimento 2). Os achados deste trabalho mostraram que, ao contrário do embrião, o desenvolvimento do intestino delgado e o peso do saco vitelino não sofreram influência da idade das matrizes. Na fase pós-eclosão, na ausência de alimento, o desenvolvimento do intestino delgado foi maior nas matrizes com 60 semanas, sendo dependente do crescimento do jejuno. A presença do alimento no lúmen teve influência na utilização das reservas do saco vitelino apenas nas matrizes com 30 semanas de idade. Os resultados deste experimento mostraram que a idade da matriz é importante fator no desenvolvimento do trato gastrointestinal do embrião, sendo fator relevante no crescimento pós-ecloão dos pintos.

In ovo peptide YY administration improves growth and feed conversion ratios in week-old broiler chicks

The effects of in ovo Peptide YY (PYY) administration on growth and feed conversion ratios in a commercial broiler line were investigated. Six hundred Ross male x Cobb female eggs were administered either 0.9% saline (control) or 600 microg/kg egg weight PYY in ovo at Day 18 of incubation. On day of hatching, 210 birds from each treatment group were randomly placed by sex into pens. Body weights at placement were not different between treatment groups. Average chick body weight and adjusted pen feed conversion ratios were improved by PYY in ovo treatment at 7 d posthatch (165.7 vs. 170.2 g, P<0.02; and 1.55 vs. 1.49, P<0.04, respectively). No significant differences between treatments were noted for these parameters at 21 or 42 d of age. These results suggest that in ovo treatment of broiler chicken eggs with gastrointestinal hormones that increase intestinal nutrient absorption, such as PYY, may enhance chick performance.

Níveis de proteína e de vitamina E para matrizes de frango de corte. 1. Efeito sobre o desempenho das matrizes, composição do ovo e desempenho da progênie

Avaliou-se o efeito da suplementação de dois níveis de proteína bruta (PB), 14 e 16%, e dois de vitamina E (VE), 25 e 250mg/kg, na dieta sobre o desempenho e composição do ovo de matrizes de frangos de corte, entre 24 e 54 semanas de idade e sobre o desempenho de suas progênies. Foram alojadas 480 fêmeas e 48 machos da linhagem Ross, com 18 semanas de idade, em 16 boxes com 30 fêmeas e 3 machos em cada um. As dietas foram à base de milho e farelo de soja, sendo todas isocalóricas (2750kcal de EM/kg). O delineamento experimental foi o inteiramente ao acaso, constituído de quatro tratamentos em esquema fatorial 2×2, sendo dois níveis de PB (NPB) e dois níveis de VE (NVE), representados por quatro repetições cada um. A produção de ovos/ave/dia, o número de ovos/ave-alojada, o peso do ovo, a viabilidade, o peso corporal das fêmeas no final do experimento e a percentagem de gema no ovo não foram influenciados (P&gt;0,05) pelos tratamentos e nem pela interação entre NVE × NPB. Menor percentagem de casca (P&lt;0,05) e maior percentagem de albúmen (P&lt;0,05) foram obtidos em ovos de aves que receberam o maior NPB na dieta, independente do NVE suplementado na dieta. Maior concentração de alfa-tocoferol na gema foi obtida em ovos de matrizes que receberam dieta suplementada com 250mg de VE/kg (P&lt;0,05). O rendimento de incubação em ambas as idades estudadas (32ª e 52ª semanas) resultou em efeitos não significativos (P&gt;0,05) dos NPB e dos NVE, representados pelo peso do ovo incubado, pela taxa de eclosão, pela razão entre o peso do ovo e o peso da progênie e pelo desempenho da progênie até a idade de abate. Porém, maior peso ao nascer (P&lt;0,01) foi encontrado na progênie proveniente de reprodutoras com 32 semanas de idade, que receberam dieta com maior NPB e maior NVE. Dieta com 14% de PB e suplementada com 25mg de VE/kg é suficiente para assegurar o desempenho produtivo e reprodutivo satisfatório de matrizes de frangos de corte durante a fase de produção.

Changes in the somatosensory evoked potentials and spontaneous electroencephalogram of broiler chickens during exposure to gas mixtures

1. Six week-old broiler chickens implanted with electroencephalogram (EEG) recording and somatosensory stimulating electrodes were exposed to either 90% argon in air, a mixture of 30% carbon dioxide and 60% argon in air or a mixture of 30% oxygen and 40% carbon dioxide (balance nitrogen) for 2 min, to determine the times to onset of changes in spontaneous EEG and the loss of somatosensory evoked potentials (SEPs) and thus unequivocal loss of consciousness. 2. In addition, after a 2 min exposure to the carbon dioxide-oxygen mixture, some broilers were allowed to recover in air and their EEGs and SEPs were continuously recorded until the return of normal EEG and SEPs. During this period, the time to return of response to comb pinching was also determined in 10 broilers. 3. All broilers exposed to either argon or the carbon dioxide-argon mixture died within 2 min, whereas, only 3 out of 17 broilers died during the 2 min exposure to the carbon dioxide-oxygen mixture. 4. During exposure to argon, unlike the other 2 gas mixtures, the majority of broilers showed high amplitude, low frequency electrical activity in the EEG on average at 10 s. The mean times to onset of EEG suppression were 17, 19 and 40 s after exposure to argon, the carbon dioxide-argon mixture and the carbon dioxide-oxygen mixture, respectively. An isoelectric EEG occurred on average at 58 and 41 s after exposure to argon and the carbon dioxide-argon mixture, respectively. An isoelectric EEG did not occur in broilers which were exposed to the carbon dioxide-oxygen mixture. 5. The SEPs were abolished in broilers on average 32 and 24 s after exposure to argon and the carbon dioxide-argon mixture, respectively. During exposure of broilers to the carbon dioxide-oxygen mixture the SEPs were abolished in the majority of birds on average at 47 s, however, 2 out of 14 birds retained their SEPs for the entire period of 2 min exposure to this gas mixture. 6. During the recovery after exposure to the carbon dioxide-oxygen mixture, response to comb pinching and SEPs returned either at the time of, or soon after, the onset of high frequency electrical activity in the suppressed EEG of broilers. The mean times to return of response to comb pinching and SEPs were 52 and 43 s, respectively. 7. Based on the time to onset of EEG suppression or loss of SEPs, exposure of broilers to either 90% argon in air, or a mixture of 30% carbon dioxide and 60% argon in air, resulted in quicker loss of consciousness than during exposure to a mixture of 40% carbon dioxide, 30% oxygen and 30% nitrogen. The time to return of consciousness after a 2 min exposure to the carbon dioxide-oxygen mixture was also found to be rapid.

Why are young broiler chickens fatter than layer-strain chicks?

1. 1. The abdominal fat pads of 5 week-old broiler and layer chicks incorporated 6.0 and 3.9% of intravenously-injected 14C-labelled very low density lipoproteins respectively. 2. 2. These proportions of total plasma lipoprotein flux were sufficient to account for about 65–70% of the rate of fat deposition in broilers, but were more than 4-fold greater than that the rate of fat deposition in layers. 3. 3. [ 14C]Palmitate taken up into adipose tissue of layer chicks had a t 1 4 of 2–3 days. 4. 4. There was no significant turnover of adipose tissue triglycerides in broilers and this appears to be a major reason for their relative fatness.