Evaluation of fatty acid metabolism and innate immunity interactions between commercial broiler, F1 layer × broiler cross and commercial layer strains selected for different growth potentials

Background： The broiler industry has undergone intense genetic selection over the past 50 yr. resulting in improvements for growth and feed efficiency, however, significant variation remains for performance and growth traits. Production improvements have been coupled with unfavourable metabolic consequences, including immunological trade-offs for growth, and excess fat deposition. To determine whether interactions between fatty acid（FA） metabolism and innate immunity may be associated with performance variations commonly seen within commercial broiler flocks, total carcass lipid %, carcass and blood FA composition, as wel as genes involved with FA metabolism, immunity and cel ular stress were investigated in male birds of a broiler strain, layer strain and F1 layer × broiler cross at d 14 post hatch. Heterophil：lymphocyte ratios, relative organ weights and bodyweight data were also compared.Results： Broiler bodyweight（n = 12） was four times that of layers（n = 12） by d 14 and had significantly higher carcass fat percentage compared to the cross（n = 6; P = 0.002） and layers（P = 0.017） which were not significantly different from each other（P = 0.523）. The carcass and whole blood FA analysis revealed differences in the FA composition between the three groups indicating altered FA metabolism, despite al being raised on the same diet. Genes associated with FA synthesis andβ-oxidation were upregulated in the broilers compared to the layers indicating a net overal increase in FA metabolism,which may be driven by the larger relative liver size as a percentage of bodyweight in the broilers. Genes involved in innate immunity such as TLR2 and TLR4, as wel as organel e stress indicators ERN1 and XBP1 were found to be nonsignificant, with the exception of high expression levels of XBP1 in layers compared to the cross and broilers. Additional y there was no difference in heterophil： lymphocytes between any of the birds.Conclusions： The results provide evidence that genetic selection may be associated with altered metabolic processes between broilers, layers and their F1 cross. Whilst there is no evidence of interactions between FA metabolism, innate immunity or cel ular stress, further investigations at later time points as growth and fat deposition increase would provide useful information as to the effects of divergent selection on key metabolic and immunological processes.

Towards the control of necrotic enteritis in broiler chickens with in-feed antibiotics phasing-out worldwide

Poultry production has undergone a substantial increase compared to the livestock industries since 1970.However, the industry worldwide is now facing challenges with the removal of in-feed antibiotics completely or gradually, as the once well-controlled poultry diseases have re-emerged to cause tremendous loss of production. Necrotic enteritis(NE) is one of the most important diseases which costs the industry over two billion dollars annually. In this paper, we review the progress on the etiology of NE and its control through dietary modifications, pre-and probiotics, short chain fatty acids, and vaccination. The other likely measures resulted in the most advances in the toxin characterization are also discussed. Vaccine strategies may have greater potential for the control of NE mainly due to clearer etiology of NE having been elucidated in recent years with the identification of necrotic enteritis toxin B-like(NetB) toxin. Therefore, the use of alternatives to in-feed antibiotics with a better understanding of the relationship between nutrition and NE, and limiting exposure to infectious agents through biosecurity and vaccination, might be a tool to reduce the incidence of NE and to improve gut health in the absence of in-feed antibiotics. More importantly, the combinations of different measures may achieve greater protection of birds against the disease. Among all the alternatives investigated, prebiotics, organic acids and vaccination have shown improved gastrointestinal health and thus, have potential for the control of NE.

Use of Lactobacillus johnsonii in broilers challenged with Salmonella sofia

The effects of Lactobacillus johnsonii(L. johnsonii) on gut microflora, bird performance and intestinal development were assessed using 288 one-day-old Cobb broilers challenged with Salmonella sofia(S.sofia). The experiment was a 3×2 factorial design which consisted of three treatments, a negative control(NC) with no additives, a positive control(PC) containing antimicrobials(zinc-bacitracin, 50 mg/kg) and a probiotic group(Pro), and with the two factors being unchallenged or challenged with S. sofia.A probiotic preparation of L. johnsonii(10~9 cfu/chick) was administered to chicks individually by oral gavage on days 1, 3, 7 and 12. Chicks were individually challenged with S. sofia(10~7 cfu/chick) by oral gavage on d 2, 8 and 13. Results showed that the challenge itself markedly reduced(P < 0.05) bird performance and feed intake. And, transient clinical symptoms of the infection with S. sofia were observed from the second time they were challenged with S. sofia in the negative challenge groups. The novel probiotic candidate L. johnsonii reduced the number of S. sofia and Clostridium perfringens in the gut environment, and improved the birds’ colonization resistance to S. sofia.

Dietary composition affects odour emissions from meat chickens

Abatement of odour emissions has become an important consideration to agricultural industries,including poultry production. The link between diet and odour emissions was studied in two experiments using Ross 308 male meat chickens reared in specially designed chambers in a climate controlled room. In the first experiment, two treatments were compared using three replicates of two birds per chamber. Two wheat-soy based treatment diets were formulated with or without canola seed, an ingredient rich in sulfur amino acids, Treatment 1(T1) had 13,39 MJ/kg ME(as fed) and used 60 g/kg canola seed without corn while Treatment 2(T2) contained 12.90 MJ/kg ME(as fed) and used 150 g/kg corn without canola seed. In the second experiment, birds were assigned to three dietary treatments of five replicates with five birds per replicate(chamber). The basal starter, grower and finisher diets in the control group(SBM group) contained soybean meal in the range of 227-291 g/kg(as fed) as the main protein source. The other treatments(CM and MBM groups) contained either high levels of canola meal(174-190 g/kg) or meat meal(74-110 g/kg) at the expense of soybean meal. In both experiments, diets were isocaloric, isonitrogenous and contained similar digestible amino acid contents as per 2007 Aviagen Ross 308 guidelines. Emissions of odour were measured using Fourier transform infrared(FTIR) spectroscopy. In both experiments, major odorous compounds detected included 2,3-butanedione(diacetyl),2-butanone, dimethyl disulfide, methyl mercaptan, ethyl mercaptan, 2-butanol, 3-methyl-butanal,phenol and m-cresol. In the first experiment, Tl(with canola seed) produced higher concentration of methyl mercaptan(P < 0.05) and lower diacetyl(P < 0.01) than T2. In the second experiment, methyl mercaptan emission was higher in SBM group(P = 0.01) and total elemental sulfur were higher in SBM and CM groups up to day 24(P < 0.01). Results of these experiments indicated a direct link between diet and odour emissions from meat chickens.

Performance,litter quality and gaseous odour emissions of broilers fed phytase supplemented diets

The effect of graded levels of phytase on performance, bone characteristics, excreta/litter quality and odorant emissions was examined using 720 Ross 308 male d-old broilers. A 2 x 4 factorial arrangement of treatments was employed with 6 replicates of 15 birds per pen. Factors were: diets-positive and negative control(PC, NC); phytase-0, 500,1,000.1,500 FTU/kg. The PC was formulated to meet the 2014 Ross 308 nutrient specifications, whereas the NC was formulated with lower Ca(-1.4 g/kg), available P(-1.5 g/kg), Na(-0.3 g/kg), dLys(-0.2 g/kg) and MEn(-0.28 MJ/kg) equivalent to nutrient matrix values for 500 FTU/kg phytase in the starter,grower and finisher periods(i.e.,downspec diet). On d 24, phytase decreased FCR by 1.6, 4.3 and 4.6 points at inclusion levels of 500.1,000 and 1,500 FTU/kg, respectively(P < 0.01) across all diets. Phytase by diet interactions on BW gain were observed on d 24 and 35(P < 0.01). The effect of phytase was much more pronounced in the NC diet as compared with the PC diet.On d 24, phytase increased BW gain by 37, 55 and 68 g in the PC and 127.233 and 173 g in the NC at 500,1,000 and 1,500 FTU/kg, respectively. Diet by phytase interactions were also observed for tibia ash, litter quality and water to feed intake ratio(P < 0.01) with higher phytase effect in NC as compared with PC.Neither diet nor phytase impacted excreta moisture content on d 18 or 21(P> 0.05). Solid phase microextraction gas chromatography-mass spectrometry(SPME-GC-MS) analysis of gaseous emissions on d 39 indicated no difference in the emission of alcohols, aldehydes, ketones, volatile fatty acids and phenols between treatments(P> 0.05). The results indicate that phytase has greater benefits when formulated using nutrient matrix values as compared with adding it over the top in an already nutrient sufficient diet. The later method would be expected to increase feed costs without concomitant performance benefits.

Novel probiotics: Their effects on growth performance, gut development, microbial community and activity of broiler chickens

A total of 294 one-day-old Cobb broiler chickens were used to investigate the effects of four Lactobacillus strains on gut microbial profile and production performance. The six dietary treatments, each with 7 replicates were: 1) basal diet(negative control), 2) one of four strains of Lactobacillus(tentatively identified as Lactobacillus johnsonii, Lactobacillus crispatus, Lactobacillus salivarius and an unidentified Lactobacillus sp.) and 3) basal diet with added zinc-bacitracin(ZnB, 50 mg/kg). Results showed that the addition of probiotic Lactobacillus spp. to the feed did not significantly improve weight gain, feed intake and feed conversion rate(FCR) of broiler chickens raised in cages during the 6-week experimental period,but tended to increase the number of total anaerobic bacteria in the ileum and caeca, and the number of lactic acid bacteria and lactobacilli in the caeca; and to significantly increase the small intestinal weight(jejunum and ileum). Furthermore, all 4 probiotics tended to reduce the number of Enterobacteria in the ileum, compared with the control treatments. The probiotics did not affect the p H and the concentrations of short chain fatty acids(SCFA) and lactic acid in both the ileum and caeca.

Delivery routes for probiotics: Effects on broiler performance,intestinal morphology and gut microflora

Four delivery routes, via, feed, water, litter and oral gavage, were examined for their efficacy in delivering a novel probiotic of poultry origin, Lactobacillus johnsonii, to broilers. Seven treatments of 6 replicates each were allocated using 336 one-day-old Cobb broiler chicks. The treatments consisted of a basal diet with the probiotic candidate, L. johnsonii, added to the feed, and three treatments with L. johnsonii added to the drinking water, sprayed on the litter, or gavaged orally. In addition, a positive control treatment received the basal diet supplemented with zinc-bacitracin(Zn B, 50 mg/kg). The probiotic strain of L.johnsonii was detected in the ileum of the chicks for all four delivery routes. However, the addition of L.johnsonii as a probiotic candidate did not improve body weight gain, feed intake and feed conversion ratio of broiler chickens raised on litter during the 5-week experimental period regardless of the route of administration. The probiotic treatments, regardless of the routes of delivery, affected(P < 0.05) the pH of the caecal digesta and tended(P = 0.06) to affect the p H of the ileal digesta on d 7, but the effect disappeared as the birds grew older. All probiotic treatments reduced the number of Enterobacteria in the caeca on d 21, and tended(P < 0.054) to reduce it in the ileum and caeca on d 7 and in the ileum on d 21 compared with the controls. The probiotic also tended to increase the number of lactic acid bacteria and lactobacilli in the ileum and caeca on d 7, but this trend was not evident on d 21. The trend appeared most pronounced when the probiotic was delivered orally or via litter. The probiotic also decreased(P <0.05) the population of Clostridium perfringens rapidly from an early age to d 21 in the caeca, leading to a3-fold decrease in the number of C. perfringens between d 7 and 21. It also showed that the probiotic treatment presented the lowest number of C. perfringens in the caeca. Delivery of the probiotic through feed, water and litter increased(P <0.01) the weight of the pancreas on d 21, but the probiotic did not affect other morphometric parameters of the gut. Furthermore, the probiotic did not affect the p H and the concentrations of short chain fatty acids and lactic acid in either the ileum or caeca.

In vitro growth of gut microbiota with selenium nanoparticles

The application of nanoparticles rose steeply in the last decade,where they have become a common ingredient used in processed human food,improving food properties such as shelf life and appearance.Nanoparticles have also attracted considerable interest to the livestock industry,due to their efficacy in intestinal pathogen control,with the regulatory and consumer driven push for the removal of antibiotic growth promoters.The influence of selenium(Se) nanoparticles was investigated on a diverse and mature broiler caecal microbiota using in vitro culturing and 16 S rRNA gene sequencing methods for microbiota characterisation.Caecal microbiota was collected from 4 traditionally grown heritage roosters and grown for 48 h,in the presence and absence of Se nanoparticles,with 2 technical replicates each.The effect of rooster as a biological variable strongly overpowered the effects of nano-Se in the media,resulting in moderate effects on the structure and diversity of the caecal microbial community.However the nanoparticles showed a significant reduction(P <0.05) in the abundance of an emerging poultry pathogen,Enterococcus cecorum identical operational taxonomic units(OTU),which could be of notable interest in poultry production for targeted E.cecorum control without significant disturbance to the total microbial community.

Ultrastructure of the gastro intestinal tract of healthy Japanese quail(Coturnix japonica) using light and scanning electron microscopy

The Japanese quail(Coturnix japonica) are popular both as an alternative protein source and as a model of choice for scientific research in several disciplines. There is limited published information on the histological features of the intestinal tract of Japanese quail. The only comprehensive reference is a book published in 1969. This study aims to fill that niche by providing a reference of general histological features of the Japanese quail, covering all the main sections of the intestinal tract. Both light and scanning electron microscope(SEM) images are presented. Results showed that the Japanese quail intestinal tract is very similar to that of the chicken with the exception of the luminal koilin membrane of the gizzard. Scanning electron microscopic photomicrographs show that in the Japanese quail koilin vertical rods are tightly packed together in a uniform manner making a carpet-like appearance. This differs in chicken where the conformations of vertical rods are arranged in clusters.