Young Broiler Research Articles

Chondronecrosis with osteomyelitis in broilers: Further defining a bacterial challenge model using the wire flooring model

Lameness in broiler chickens is a significant animal welfare and financial issue. Bacterial chondronecrosis with osteomyelitis (BCO) leading to lameness can be enhanced by rearing young broilers on wire flooring. Using the wire floor system, we identified Staphylococcus agnetis as the predominant isolate in BCO of the proximal tibiae and femora, and blood of lame broilers. Administration of S. agnetis isolates in water can induce lameness. We now report that the wire floor system increases bacterial translocation into the blood stream. We have also determined that approximately 105 CFU/mL is the minimum effective dose in the drinking water and that challenge at 10, 20, or 30 days of age produces similar incidences of lameness. BCO isolates of S. agnetis are much more effective than other Staphylococcus species and can overwhelm the protective effects of some commercial probiotics. Finally, we also demonstrated that the BCO lameness induced by administration of S. agnetis in the drinking water is transmissible to unchallenged broilers in the same pen.

Influence of soybean bioactive peptides on growth performance, nutrient utilisation, digestive tract development and intestinal histology in broilers

SummaryA biologically active peptide derived from soybeans by enzymatic hydrolysis was evaluated for its potential benefits on chicken growth performance, apparent ileal nutrient digestibility and intestinal histology in young broilers. Seven broiler starter diets, based on maize and soybean meal, were formulated to contain 0.0, 1.0, 2.0, 3.0, 4.0, 5.0 and 6.0 g/kg of a commercial soybean bioactive peptide (SBP) product (Fortide, Chengdu Mytech Biotech Co. Ltd., Chengdu, Sichuan, China). All diets were equivalent in respect of energy density, and digestible protein, amino acids, and other nutrients. A total of 336, one-day-old male broilers (Ross 308) were allocated to 42 cages (eight birds/cage), which were randomly assigned to the six dietary treatments. There was no significant effect of SBP on weight gain and feed intake of the birds. A significant (P < 0.01) effect of SBP was observed for FCR. Inclusion of 1.0, 2.0, 3.0 and 4.0 g SBP/kg of feed resulted in similar FCR values to the diet with no SBP, addition of SBP to the diets at 5.0 and 6.0 g/kg of feed resulted in lower (P < 0.05) FCR compared to the diet with no SBP. Inclusion of SBP had no effect (P > 0.05) on apparent ileal digestibility of nutrients and energy utilisation. Though not statistically significant, SBP inclusion, regardless of level, resulted in 5.7% and 6.3% increases in digestibility of dry matter and nitrogen, respectively. Birds receiving no SBP had the shortest villi and those fed SBP at 3.0 and 6.0 g/kg of feed tended (P = 0.075) to have the greatest villus height. The current findings suggested that including SBP in broiler diets may benefit production through improving feed efficiency, and, to some extent, nutrient digestion and intestinal histology parameters.

Whole genome sequencing of Fowl aviadenovirus A - a causative agent of gizzard erosion and ulceration, in adult laying hens

Gizzard erosion and ulceration (GEU) caused by fowl aviadenovirus serotype 1 (FAdV-1) of the species Fowl aviadenovirus A (FAdV-A) represents an economically important problem in poultry production. The disease affects mostly young chicken broilers or layers before production.In this study, an unusual GEU outbreak in a flock of laying hens at 38weeks of age is described. The affected flock showed elevated mortality rates, with the highest number of dead birds appearing between the 39th and 40th week of life, with a subsequent reduction in laying performance and decreased total egg weight. Post-mortem examination showed the presence of erosion in multiple areas of the gizzard, with wall perforation in the proximity of the interventriculus. FAdV antibodies were detected in all examined sera with an ELISA assay. The virus was isolated from pathologically altered gizzards. PCR, subsequent sequencing and phylogenetic analysis of the partial hexon gene confirmed the presence of FAdV-A DNA.To investigate the molecular background of FAdV-A which causes GEU in adult hens, whole genome sequencing was performed on two FAdV-A strains - strain W-15, obtained from the outbreak described in this study and strain 61/11z, isolated from a GEU outbreak in 3-week-old broiler chickens in 2011.The genome size of FAdV-A W-15 is 43,849bp. Genome sequence and genome organization resembles those of the reference, apathogenic CELO strain and the newly sequenced GEU strain, 61/11z.Most amino acid changes, between CELO and GEU strains, were observed in ORF0, ORF1, ORF14, IVa2, polymerase, pIIIa, penton base and fiber-2. Analysis conducted on the translated ORFs revealed that W-15 and 61/11z are nearly identical, with the highest rate of amino acid mutations in pTP, 100K, ORF9 and ORF10.In this study, the occurrence of GEU, caused by FAdV-1 infection, in adult layer chickens and the effects of such infection on egg production parameters are described in detail. Moreover, the whole genome sequences of two pathogenic, GEU inducing FAdV-A strains have been provided and characterized for the first time, which in the future will help to pinpoint the viral factors involved in pathogenicity.

Effect of Broiler Breeder Age on the Intestinal Mucosa Development of the Embryos at 20 Days of Incubation

This study investigated the effect of broiler breeder age on the morphological development of the small intestine broiler embryos (villus height, crypt depth, microvillus height, and villus density) at 20 day of incubation. Eggs obtained from 30- and 60-wk-old broiler breeders were used. The results showed that embryos from older broiler breeders presented longer villi in the duodenum, jejunum, and ileum compared with younger broiler breeders. In addition, embryos from older broiler breeders presented deeper crypts in the jejunum and ileum, longer microvilli in jejunal enterocytes, and lower villus density (microvillus number/mm2) in the duodenum and ileum than younger breeders. These results suggest that breeder age influences the gut mucosa development of broiler embryos. Embryos from older broiler breeder showed greater development of the small intestine mucosa than those from younger broiler breeder.

Effects of diet form and particle size on performance, digestive tract development and intestinal mast cell numbers in young broiler chicks

Effects of diet form and particle size on performance, digestive tract development and intestinal mast cell numbers in young broiler chicks

EFFECTS OF FEEDING MUNG BEANS (VIGNARADIATE) ON THE BROILER PERFORMANCE

This experiment was carried out at the poultry research farm belonging to Faculty of Agriculture Science, Sulaimani University Bakrajo during the period from 24/10/2014 to 10/12/2014. This experiment was designed to study the effect of feeding different levels of mung beans (Vignaradiata) on the broiler performance. A total of 99 one-day old broiler chicks (ross 308) were randomly divided in to three experimental treatments with 3 replicates, each replicate contains 11 birds reared on floor cages. The first group was considered as (control) while the second group fed on diet, had 5% mung bean and the third group, received diet contain 10% mung bean. The effects of feeding mung beans at various two levels on the performance of young broiler chicks, for both trials there was no significant effect (P≥0.05) of diet contain mung beans on weight gain or feed conversion of broilers.

The level and source of free-methionine affect body composition and breast muscle traits in growing broilers1

Although dietary Met, as the first limiting amino acid (AA), has been extensively studied for poultry, little is known about how the supply and source of free Met affect tissue composition. The purpose of this study was to investigate the effect of feeding young broiler chickens with a deficient or sufficient TSAA (Met+Cys) supply, using either dl-Met (dl-Met+ and dl-Met–, for respectively diets sufficient and deficient in TSAA) or dl- 2-hydroxy-4-methylthiobutyric acid (HMTBA+ and HMTBA–, for respectively diets sufficient and deficient in TSAA) as a Met source on tissue composition and breast muscle traits. For both Met sources, the deficient diets were formulated to provide true digestible Met:Lys and TSAA:Lys respectively 45% and 30% below that of the sufficient diets. Performance and tissue weights were affected by the Met supply but not by the Met source. In TSAA-deficient chickens, ADG and FCR, and protein content in empty body and pectoralis major muscles (PM) were lower than in TSAA-sufficient chickens (P < 0.05). Reducing the Met content of the diet increased the redness value of PM (a*) and the hue angle (H°; P < 0.01). The source of Met affected body AA composition and the partitioning of body Cys among tissues (P < 0.05). In TSAA-deficient birds, body Cys mass decreased in the commercial carcass and PM, but increased in the rest of the body (P < 0.01). The Met source also had an impact on the Cys mass, which was reduced in the commercial carcass and PM of dl-Met birds, but higher in the rest, especially in the feathers of TSAA-deficient birds (P < 0.05). The Met source, supply, or both altered the AA composition of the empty body, mostly in the commercial carcass. In conclusion, a dietary TSAA deficiency altered performance, tissue composition and quality traits of PM of broilers. There was no impact between dietary dl-Met and dl-HMTBA on performance or muscle weight, although the Met source affected the partitioning of Cys among tissues.

Correction: Transcriptome Analysis Reveals Regulation of Gene Expression for Lipid Catabolism in Young Broilers by Butyrate Glycerides

[This corrects the article DOI: 10.1371/journal.pone.0160751.].

Transcriptome Analysis Reveals Regulation of Gene Expression for Lipid Catabolism in Young Broilers by Butyrate Glycerides.

Background & AimsButyrate has been shown to potently regulate energy expenditure and lipid metabolism in animals, yet the underlying mechanisms remain to be fully understood. The aim of this study was to investigate the molecular mechanisms of butyrate (in the form of butyrate glycerides, BG)-induced lipid metabolism at the level of gene expression in the jejunum and liver of broilers.Methodology/Principal FindingsTwo animal experiments were included in this study. In Experiment 1, two hundred and forty male broiler chickens were equally allocated into two groups: 1) basal diet (BD), 2) BG diets (BD + BG). Growth performance was compared between treatments for the 41-day trial. In Experiment 2, forty male broiler chickens were equally allocated into two groups. The general experimental design, group and management were the same as described in Experiment 1 except for reduced bird numbers and 21-day duration of the trial. Growth performance, abdominal fat deposition, serum lipid profiles as well as serum and tissue concentrations of key enzymes involved in lipid metabolism were compared between treatments. RNA-seq was employed to identify both differentially expressed genes (DEGs) and treatment specifically expressed genes (TSEGs). Functional clustering of DEGs and TSEGs and signaling pathways associated with lipid metabolism were identified using Ingenuity Pathways Analysis (IPA) and DAVID Bioinformatics Resources 6.7 (DAVID-BR). Quantitative PCR (qPCR) assays were subsequently conducted to further examine the expression of genes in the peroxisome proliferator-activated receptors (PPAR) signaling pathway identified by DAVID-BR. Dietary BG intervention significantly reduced abdominal fat ratio (abdominal fat weight/final body weight) in broilers. The decreased fat deposition in BG-fed chickens was in accordance with serum lipid profiles as well as the level of lipid metabolism-related enzymes in the serum, abdominal adipose, jejunum and liver. RNA-seq analysis indicated that dietary BG intervention induced 79 and 205 characterized DEGs in the jejunum and liver, respectively. In addition, 255 and 165 TSEGs were detected in the liver and jejunum of BG-fed group, while 162 and 211 TSEGs genes were observed in the liver and jejunum of BD-fed birds, respectively. Bioinformatic analysis with both IPA and DAVID-BR further revealed a significant enrichment of DEGs and TSEGs in the biological processes for reducing the synthesis, storage, transportation and secretion of lipids in the jejunum, while those in the liver were for enhancing the oxidation of ingested lipids and fatty acids. In particular, transcriptional regulators of THRSP and EGR-1 as well as several DEGs involved in the PPAR-α signaling pathway were significantly induced by dietary BG intervention for lipid catabolism.ConclusionsOur results demonstrate that BG reduces body fat deposition via regulation of gene expression, which is involved in the biological events relating to the reduction of synthesis, storage, transportation and secretion, and improvement of oxidation of lipids and fatty acids.

The use of perches and platforms by broiler chickens

Perching is considered an integral part of chicken behaviour, and is suggested to alleviate leg problems and enhance mobility in broilers, as it stimulates diversification of locomotion. The use of perches is, however, low in broilers. There is a need for investigation of elevated structures that are better accepted by meat type chickens.We compared elevated plastic platforms with wooden perches on a commercial farm. The data comprises 4 flocks with perches and 6 flocks with platforms, as well as control flocks for both. The use of these structures and the activity of broilers were recorded from video. Activity was measured as bouts of movements in an area with no platforms. The behaviour of the birds was analysed at 3 ages, during both day and night.The use of platforms exceeded the use of perches. Broilers used low perches (10cm) more than high perches (30cm) at the age of 32days (P=0.001). Platforms were used more during day time than during nights especially in younger broilers (P=0.046). Broilers became more inactive as they got older and were less active during the nights. The presence of platforms had no effect on general activity. Because the perches were mostly unused their effect on bird activity was not analysed.The frequent use of platforms indicates they are better suited for broilers than perches. However, platforms did not appear to stimulate general activity. The fact that the broilers used platforms to a high degree indicate that broilers are motivated to use elevated structures or driven by high animal densities. It might be that the low perch use is due to physical challenges and not to a lack of motivation to use elevated structures.

In vitro bile acid-binding capacity of dietary fibre sources and their effects with bile acid on broiler chicken performance and lipid digestibility

A 4 × 2 factorial experiment was conducted to study the effect of feeding diets-containing dietary fibre (DF) sources and a source of bile acid (BA) on growth performance and lipid metabolism. In addition, in vitro BA-binding capacity of fibre sources was investigated.A total of 256 one-d-old male broiler chickens (Ross 308) were assigned to DF sources [maize-soybean meal (control, C), or 30 g/kg of wheat bran (WB), barley bran (BB) or soybean hulls (SH)] and BA (with or without 1.5 g Na-deoxycholate/kg). Each treatment was replicated 4 times with 8 broiler chickens per cage.The highest in vitro BA-binding capacity was observed with BB (8.76 mg/g BB). From 0 to 21 d, with the addition of BA, the average daily feed intake (ADFI) decreased in broiler chickens fed on the C, WB or BB diets, while there was no difference with the SH diet. With added BA, the average daily gain decreased in broiler chickens fed on the C or SH diets, but it did not change in those fed on the other diets. The addition of BA decreased feed conversion ratio (FCR) in broiler chickens fed on the BB or WB diets, but it increased in those fed on the C or SH diets. Interaction results indicated that the apparent ileal digestibility of lipid increased in broiler chickens fed the C and other DF diets with BA compared to those fed the diets without BA. The addition of BA decreased the pancreas lipase activity (PLA) in broiler chickens fed on the C diet compared to those fed the C diet without BA, while no changes observed in those fed the DF diets with or without BA. No interaction was observed in total liver bile acid (TLBA).The WB, BB and SH with little Na-deoxycholate-binding capacity (<10 mg/g of DF) under in vitro conditions had particular effects with BA on the measured criteria in broiler chickens. The magnitude of improvement in digestibility of lipid with the addition of BA depends on the source of fibre used and the addition of BA in DF diets had little effect on growth performance in young broiler chicken diets.

Influence of partial replacement of ground wheat with whole wheat and exogenous enzyme supplementation on growth performance, nutrient digestibility and energy utilization in young broilers.

This study investigated the influence of pre-pelleting inclusion of whole wheat (WW) and exogenous enzyme supplementation on growth performance, coefficient of apparent ileal nutrient digestibility (CAID) and apparent metabolizable energy (AME) in broilers fed wheat-based pelleted diets. A 2×3 factorial arrangement of treatments was used with two methods of wheat inclusion [622g/kg ground wheat (GW) and 250g/kg WW replaced GW (wt/wt) pre-pelleting (PWW)] and three enzymes (xylanase, phytase and xylanase plus phytase). A total of 288, one-day-old male broilers (Ross 308) were individually weighed and allocated to 36 cages (8 broilers/cage), and the cages were randomly assigned to the six dietary treatments. Birds fed PWW diets gained more (p<0.05) weight than those fed GW diets. There was no effect (p>0.05) of WW inclusion on feed intake (FI). Phytase alone increased (p<0.05) FI compared to xylanase or the combination. Whole wheat inclusion increased (p<0.05) the gain-to-feed ratio (G:F). Feeding xylanase plus phytase and phytase-added diets resulted in the greatest and lowest G:F, respectively, with xylanase supplemented diets being intermediate. Birds fed PWW diets had greater (p<0.05) relative gizzard weights than those fed GW diets. There was no effect (p>0.05) of WW inclusion on the CAID of nitrogen (N), starch and fat. Combination of xylanase and phytase resulted in greater (p<0.05) digestibility of N, starch and fat than that of individual additions. Feeding PWW diets resulted in greater (p<0.05) AME values than GW diets. Combination of xylanase and phytase increased (p<0.05) the AME compared to the diets with individual additions of xylanase or phytase. The current results suggest that the influence of pre-pelleting WW inclusion and exogenous enzymes on nutrient digestibility and broiler performance is not additive.

Interactive effects of dietary protein source and exogenous protease on growth performance, immune competence and jejunal health of broiler chickens

A total of 672 male 7-day-old broiler chicks were used in a 14-day cage study to evaluate the interactive effects of dietary protein source and exogenous protease on nutrient digestibility and intestinal physiology. Birds were fed a common starter diet from Days 0 to 7 and switched to experimental diets from Days 7 to 21. Four corn-based dietary treatments were arranged in a 2 × 2 factorial arrangement with factors being two major sources of protein [soybean meal (SBM) or canola meal] and diets offered with or without exogenous protease. Bodyweight gain and gain:feed were higher (P &lt; 0.001) in the diets based on SBM than in the diets based on canola meal and protease was more effective (P &lt; 0.05) in enhancing performance in SBM-based diets. Ileal nitrogen digestibility was increased (P &lt; 0.01) by protease use in diets based on both major protein sources. However, ileal digestible energy was increased (P &lt; 0.05) by protease only in the SBM-based diet resulting in an interaction between diet protein source and exogenous protease. Jejunal villus height tended to be higher (P = 0.07) in birds fed diets based on SBM and protease use increased (P &lt; 0.05) crypt depth only in the SBM-free diets resulting in a significant interaction between protein source and protease use. Patterns of gene expression in jejunal tissue suggested that both dietary protein source and exogenous protease influence the expression of genes responsible for mucin secretion, amino acid transport and immune functionality in an age-dependent manner. It can be concluded that SBM may be a more suitable protein source for young broiler chickens than canola meal and that use of canola meal as a major source of dietary protein may have negative implications for performance, nitrogen digestibility and gut health. However, exogenous protease appears to be more compatible with substrates presented by SBM than is the case for canola meal based on advantages conferred in nutrient digestibility and performance. The beneficial effects of exogenous protease may be linked both to enhanced protein and energy digestibility and improved gut morphological characteristics, secretory and absorptive dynamics and immune resilience.

Caffeine causes pulmonary hypertension syndrome (ascites) in broilers.

Pulmonary hypertension syndrome (PHS), or ascites, is characterized by elevated pulmonary arterial pressure and pulmonary vascular resistance accompanied by right ventricular hypertrophy (RVH) and fluid accumulation in the abdominal cavity. Experimental models are required for triggering PHS to study the pathogenesis of this syndrome and to select resistant genetic lines. Caffeine increases vascular resistance and promotes systemic hypertension in mammals, but a similar effect of caffeine on the pulmonary circulation had not previously been demonstrated. Two experiments were conducted to evaluate the impact of caffeine alone (Exp. 1) or in combination with cold temperature (Exp. 2) on parameters associated with PHS in young broiler chicks. In Exp. 1, 288 chicks were distributed among 24 pens and brooded at standard environmental temperatures, and on d 3 through 42 caffeine was added to the water at doses of 0 (control), 6.25, 12.5, 25, 50, and 100 mg/(kg BW·d). In Exp. 2, 192 chicks were distributed among 16 pens and brooded at cool environmental temperatures, and on d 3 through 42 caffeine was added to the water at doses of 0 (control), 15, 30, and 45 mg/(kg BW·d). In Exp. 1 caffeine administered at or above 12.5 mg/(kg BW·d) induced severe PHS and resulted in acute mortality and RVH ( < 0.05). Hematocrit also slightly increased by caffeine supplementation ( = 0.07). In Exp. 2 caffeine-treated broilers exposed to cold temperatures remarkably exhibited PHS incidences and developed RVH with right ventricular to total ventricular weight ratios of 30% or greater. Moreover, hematocrit significantly increased because of caffeine supplementation in cool ambient temperature ( = 0.002). Our data demonstrate that caffeine induces high incidences of PHS in broilers, which is exacerbated by exposure to low temperatures.

Establishment of a pathogenicity index in Salmonella Enteritidis and Salmonella Typhimurium strains inoculated in one-day-old broiler chicks

Salmonella Enteritidis and Salmonella Typhimurium are responsible for causing huge economic loses in aviculture, as they lead young broiler chicks to develop clinical disease and thus increase mortality. Salmonella's pathogenicity is considered complex and multifactorial, demanding more studies that could elucidate the interaction between host and pathogen. The present study aims to evaluate the virulence of 130S. Enteritidis isolates and 70S. Typhimurium inoculated in one-day-old chicks through the establishment of a pathogenicity index. For each strain, 10 commercial chicks from the Cobb lineage were used. Then, 200µL of a solution containing 2x108 CFU of S. Enteritidis or S. Typhimurium were inoculated in the birds by intraperitoneal via. Mortality and presence of lesions such as aerosaculitis (A), perihepatitis (Ph), pericarditis (Pc), peritonitis (Pt), onfalitis (O) and cellulitis (C) were registered daily for seven days. From the second to the seventh day there was a proportional decrease in the punctuation of the time of death (TD) for each day that the bird had survived. The pathogenicity index was calculated using the following formula: PI = (TD x 5) + A + Ph + Pc + Pt + O + C. The obtainment of the PI of each bacterial sample was achieved by calculating the rate of the ten inoculated birds. Based on the obtained results, it was possible to attribute the pathogenicity value for each strain, which enabled us to classify them in groups of low (27/200), intermediate (95/200) and high (78/200) pathogenicity. The utilization of standards like time of death and presence of septicemic lesions made it possible to determine the pathogenicity rate for each strain. Besides that, the proposed model has presented dramatic differences between the high, intermediate and low pathogenicity groups, which makes this mechanism useful for further classification of strains isolated in poultry farms.

경기지역 육계의 콕시듐 감염실태 조사

Abstract Protozoan parasite, the genus Eimeria , causes an intestinal disease, coccidiosis, in young broilers. Coccidiosis induces significant economic loss in poultry production. This study was designed to identify the prevalence of Eimeria spp. in broilers in Gyeonggi province, Korea. Fecal samples from broilers at 94 farms were collected in two chicken slaughterhouses between March and June 2015. Eimeria in-fection was determined by microscopic examination and PCR using ITS-1 region. The prevalence of Eimeria was 58.5% (55 of 94). E . acervulina was identified in 96.4% of samples, E . tenella in 81.8%, E . maxima in 12.7%, E . praecox in 12.7%, E . brunetti in 5.5%, E . necatrix in 1.8%, and E . mitis in 1.8%. Body weight (BW) of broilers infected with both E . tenella and E . acervulina (mean=1.53±0.19 B kg) was significantly lower than broilers with E . acervulina positive/ E . tenalla negative (mean=1.74±0.07 A kg) or Eimeria negative (mean=1.65±0.15 A kg) (Duncan’s multiple range test,

Melatonin modulates monochromatic light-induced GHRH expression in the hypothalamus and GH secretion in chicks

To study the mechanism by which monochromatic lights affect the growth of broilers, a total of 192 newly hatched broilers, including the intact, sham-operated and pinealectomy groups, were exposed to white light (WL), red light (RL), green light (GL) and blue light (BL) using a light-emitting diode (LED) system for 2 weeks. The results showed that the GHRH-ir neurons were distributed in the infundibular nucleus (IN) of the chick hypothalamus. The mRNA and protein levels of GHRH in the hypothalamus and the plasma GH concentrations in the chicks exposed to GL were increased by 6.83–31.36%, 8.71–34.52% and 6.76–9.19% compared to those in the chicks exposed to WL (P=0.022–0.001), RL (P=0.002–0.000) and BL (P=0.290–0.017) in the intact group, respectively. The plasma melatonin concentrations showed a positive correlation with the expression of GHRH (r=0.960) and the plasma GH concentrations (r=0.993) after the various monochromatic light treatments. After pinealectomy, however, these parameters decreased and there were no significant differences between GL and the other monochromatic light treatments. These findings suggest that melatonin plays a critical role in GL illumination-enhanced GHRH expression in the hypothalamus and plasma GH concentrations in young broilers.

Influence of Palm Kernel Meal Inclusion and Exogenous Enzyme Supplementation on Growth Performance, Energy Utilization, and Nutrient Digestibility in Young Broilers.

The objective of the present study was to investigate the influence of palm kernel meal (PKM) inclusion and exogenous enzyme supplementation on growth performance, nitrogen-corrected apparent metabolizable energy (AMEn), coefficient of apparent ileal digestibility (CAID) and total tract retention of nutrients in young broilers fed corn-based diets. Four inclusion levels of PKM (no PKM [PKM0], 8% [PKM8], 16% [PKM16], and 24% [PKM24]) and two enzyme additions were evaluated in a 4×2 factorial arrangement of treatments. A total of 384, one-d-old male broilers (Ross 308) were individually weighed and allocated to 48 cages (eight broilers/cage), and cages were randomly assigned to eight dietary treatments. Results indicated that the inclusion of 8% and 16% PKM increased (p<0.05) the weight gain compared to the PKM0 diet. Birds fed the PKM8 diets had the highest (p<0.05) feed intake. Weight gain and feed intake were severely reduced (p<0.05) by feeding the PKM24 diet. Enzyme supplementation increased weight gain (p<0.05), independent of PKM inclusion level. In PKM0 and PKM8 diets, enzyme addition significantly (p<0.05) lowered feed conversion ratio (FCR); whereas enzyme addition had no effect on FCR of birds fed PKM16 and PKM24 diets. In PKM0 and PKM16 diets, enzyme addition significantly (p<0.05) increased CAID of nitrogen and energy but had no effect in the PKM8 and PKM24 diets. Inclusion of PKM into the basal diet, irrespective of inclusion level, enhanced (p<0.05) starch and fat digestibility. Inclusion of PKM at 16% and 24% resulted in similar CAID of neutral detergent fiber (NDF) but higher (p<0.05) than that of the PKM0 and PKM8 diets. Enzyme addition, regardless of the level of PKM inclusion, significantly (p<0.05) increased CAID of NDF. There was a significant (p<0.05) decrease in AMEn with PKM inclusion of 24%. The present data suggest that inclusion of PKM in broiler diets could be optimized if PKM-containing diets are formulated based on digestible amino acid contents and supplemented with exogenous enzymes. If amino acid digestibility and AME of PKM considered in the formulation, it can be included in broiler diets up to 16% with no deleterious effects on growth performance.

Estimating Ventilation Rates of Animal Houses through CO2 Balance

The CO 2 production rates from various animal species were measured as well as the ventilation rates (VR) in environmental rooms at Michigan State University over the course of 15 studies that considered dietary strategies to alter air emissions, including two dairy cow studies, four steer studies, two swine studies, one turkey study, four laying hen studies, and two broiler chicken studies. The objectives of this article are to summarize the baseline data on CO 2 production from various animal species and determine uncertainties of the CO 2 balance approach for estimating VR of animal houses by evaluating the model performance in these studies. In the poultry (broiler, laying hen, and turkey) and dairy studies, the CO 2 production rates per heat production of animals or respiratory quotient (RQ) showed a decreasing trend with increasing animal age or days in milk (DIM). Higher variation in CO 2 production rates per heat production of animals were observed in young broiler chicken ( 2 production rates were generally comparable with each other for each species, and the standard deviation of model residuals was about 20% to 30% of the average measured CO 2 production rate for each species except dairy cows. By only including data in which the differences between exhaust and inlet CO 2 concentrations were larger than 50 ppm, the standard deviations of model residuals were less than 32% of the average measured VR in the broiler, laying hen, swine, and steer studies. Based on the results, when using the CO 2 balance approach to estimate VR for broiler, laying hen, swine, and steer operations, a minimum of ten replicate measurements is required to achieve a margin of error less than 20% in modeled VR with 95% confidence.

AMPK and mTOR: sensors and regulators of immunometabolic changes during Salmonella infection in the chicken

Non-typhoidal Salmonella enterica induce an early pro-inflammatory response in chickens, but the response is short-lived, asymptomatic of clinical disease, results in a persistent colonization of the gastrointestinal (GI) tract, and can transmit infections to naïve hosts via fecal shedding of bacteria. The underlying mechanisms that facilitate this persistent colonization of the ceca of chickens by Salmonella are unknown. We have begun to concentrate on the convergence of metabolism and immune function as playing a major role in regulating the host responsiveness to infection. It is now recognized that the immune system monitors the metabolic state of tissues and responds by modulating metabolic function. The aim in this review is to summarize the literature that has defined a series of genotypic and phenotypic alterations in the regulatory host immune-metabolic signaling pathways in the local cecal microenvironment during the first 4 d following infection with Salmonella enterica serovar Enteritidis. Using chicken-specific kinomic immune-metabolism peptide arrays and quantitative real-time-PCR of cecal tissue during the early (4 to 48 h) and late stages (4 to 17 d) of a Salmonella infection in young broiler chickens, the local immunometabolic microenvironment has been ascertained. Distinct immune and metabolic pathways are altered between 2 to 4 d post-infection that dramatically changed the local immunometabolic environment. Thus, the tissue immunometabolic phenotype of the cecum plays a major role in the ability of the bacterium to establish a persistent cecal colonization. In general, our findings show that AMPK and mTOR are key players linking specific extracellular milieu and intracellular metabolism. Phenotypically, the early response (4 to 48 h) to Salmonella infection is pro-inflammatory, fueled by glycolysis and mTOR-mediated protein synthesis, whereas by the later phase (4 to 5 d), the local environment has undergone an immune-metabolic reprogramming to an anti-inflammatory state driven by AMPK-directed oxidative phosphorylation. Therefore, metabolism appears to provide a potential critical control point that can impact infection. Further understanding of metabolic control of immunity during infection should provide crucial information of the development of novel therapeutics based on metabolic modulators that enhance protection or inhibit infection.