Financial impacts of a housing order on commercial free range egg layers in response to highly pathogenic avian influenza.

Recent annual outbreaks of Highly Pathogenic Avian Influenza (HPAI) have led to mandatory housing orders on commercial free-range flocks. Indefinite periods of housing, after poultry have had access to range, could have production and financial consequences for free range egg producers. The impact of these housing orders on the performance of commercial flocks is seldom explored at a business level, predominantly due to the paucity of commercially sensitive data. The aim of this paper is to assess the financial and production impacts of a housing order on commercial free-range egg layers. We use a unique data set showing week by week performance of layers gathered from 9 UK based farms over the period 2020-2022. These data cover an average of 100,000 laying hens and include two imposed housing orders, in 2020/2021 and in 2021/22. We applied a random intercept linear regression to assess impacts on physical outputs and inputs, bird mortality and the impacts on revenue, feed costs and margin over feed cost. Feed use and feed costs per bird increased during the housing order which is a consequence of increased control over diet intake in housed compared to ranged birds. An increase in revenue was also found, ostensibly due to a higher proportion of large eggs produced, leading to a higher margin over feed cost. Overall, these large commercial poultry sheds were able to mitigate some of the potential adverse economic effects of housing orders. Potential negative impacts may occur dependant on the duration of the housing order and those farms with less control over their input costs.

Transcriptome analysis of differentially expressed circRNAs miRNAs and mRNAs during the challenge of coccidiosis.

Avian coccidiosis is a common enzootic disease caused by infection of Eimeria species parasites. It causes huge economic losses in the global poultry industry. Current control using anticoccidial drugs or vaccination is limited due to drug resistance and the relatively high cost of vaccines. Improving host genetic resistance to Eimeria species is considered an effective strategy for improved control of coccidiosis. Circular RNAs (circRNAs) have been found to function as biomarkers or diagnoses of various kinds of diseases. The molecular biological functions of circRNAs, miRNAs, and mRNAs related to Sasso chicken have not yet been described during Eimeria species challenge. In this study, RNA-seq was used to profile the expression pattern of circRNAs, miRNAs, and mRNAs in spleens from Eimeria tenella-infected and non-infected commercial dual-purpose Sasso T445 breed chickens. Results showed a total of 40 differentially expressed circRNAs (DEcircRNAs), 31 differentially expressed miRNAs (DEmiRNAs), and 820 differentially expressed genes (DEmRNAs) between infected and non-infected chickens. Regulatory networks were constructed between differentially expressed circRNAs, miRNAs, and mRNAs to offer insights into the interaction mechanisms between chickens and Eimeria spp. Functional validation of a significantly differentially expressed circRNA, circMGAT5, revealed that circMGAT5 could sponge miR-132c-5p to promote the expression of the miR-132c-5p target gene monocyte to macrophage differentiation-associated (MMD) during the infection of E. tenella sporozoites or LPS stimulation. Pathologically, knockdown of circMGAT5 significantly upregulated the expression of macrophage surface markers and the macrophage activation marker, F4/80 and MHC-II, which indicated that circMGAT5 might inhibit the activation of macrophage. miR-132c-5p markedly facilitated the expression of F4/80 and MHC-II while circMGAT5 could attenuate the increase of F4/80 and MHC-II induced by miR-132c-5p, indicating that circMGAT5 exhibited function through the circMGAT5-miR-132c-5p-MMD axis. Together, our results indicate that circRNAs exhibit their resistance or susceptive roles during E. tenella infection. Among these, circMGAT5 may inhibit the activation of macrophages through the circMGAT5-miR-132c-5p-MMD axis to participate in the immune response induced by Eimeria infection.

Exploring the attitudes of backyard poultry keepers to health and biosecurity.

Backyard poultry producers have been associated with outbreaks of exotic (e.g. avian influenza) and endemic (e.g. Salmonella) disease all over the world. Currently in the UK the registration of small flocks (less than 50 birds) with local authorities is voluntary therefore there is not an accurate record of how many keepers and birds there are or where they are located. This lack of information (e.g. how many birds they keep, what type of birds, biosecurity measures they implement, etc.) may compromise contingency planning in an outbreak. A questionnaire was designed and implemented to gather information that will allow some of the knowledge gaps to be filled. The questionnaire comprised a total of 63 questions divided into seven sections (characterisation of the keeper, location of the enterprise and interest in poultry, poultry husbandry, transport of poultry, details about the poultry enterprise, marketing of poultry products, and poultry health/biosecurity). The questionnaire was implemented through an online survey, which was promoted through web links in smallholders' websites, Facebook pages, the SRUC network, a course about poultry welfare, and leaflets at smallholders' festivals. The survey was open from 24th October 2016 to 10th April 2017 and 176 questionnaires were completed by target respondents. Overall, our results suggest that the level of disease identified by backyard poultry keepers is low but the majority of the backyard poultry keepers also keep other livestock species, with an associated increased risk for disease transmission between species. Almost all respondents reported implementing at least one biosecurity measure, although in the majority of cases the measures taken were not comprehensive. A lack of knowledge about the legislation concerning poultry-keeping activities was evidenced by the answers given to some questions, such as the feeding of kitchen scraps and how to dispose of dead stocks. This investigation fills gaps in knowledge which will allow industry stakeholders and policy makers to adapt their current disease programmes and contingency plans to the reality of the health and biosecurity status of backyard poultry. It also highlights that government could play a more active role in engaging with backyard poultry keepers and in finding ways to disseminate reliable information generally and about disease outbreaks specifically, to these keepers.

Erratum: Martin, J.E., et al. Welfare Risks of Repeated Application of On-Farm Killing Methods for Poultry. Animals 2018, 8, 39.

The authors wish to make the following correction to their paper[...].

Welfare Risks of Repeated Application of On-Farm Killing Methods for Poultry.

Council Regulation (EC) no. 1099/2009 on the protection of animals at the time of killing restricts the use of manual cervical dislocation in poultry on farms in the European Union (EU) to birds weighing up to 3 kg and 70 birds per person per day. However, few studies have examined whether repeated application of manual cervical dislocation has welfare implications and whether these are dependent on individual operator skill or susceptibility to fatigue. We investigated the effects of repeated application (100 birds at a fixed killing rate of 1 bird per 2 min) and multiple operators on two methods of killing of broilers, laying hens, and turkeys in commercial settings. We compared the efficacy and welfare impact of repeated application of cervical dislocation and a percussive killer (Cash Poultry Killer, CPK), using 12 male stockworkers on three farms (one farm per bird type). Both methods achieved over 96% kill success at the first attempt. The killing methods were equally effective for each bird type and there was no evidence of reduced performance with time and/or bird number. Both methods of killing caused a rapid loss of reflexes, indicating loss of brain function. There was more variation in reflex durations and post-mortem damage in birds killed by cervical dislocation than that found using CPK. High neck dislocation was associated with improved kill success and more rapid loss of reflexes. The CPK caused damage to multiple brain areas with little variation. Overall, the CPK was associated with faster abolition of reflexes, with fewer birds exhibiting them at all, suggestive of better welfare outcomes. However, technical difficulties with the CPK highlighted the advantages of cervical dislocation, which can be performed immediately with no equipment. At the killing rates tested, we did not find evidence to justify the current EU limit on the number of birds that one operator can kill on-farm by manual cervical dislocation.

Superoxide dismutase SodB is a protective antigen against Campylobacter jejuni colonisation in chickens.

Campylobacter is the leading cause of foodborne diarrhoeal illness in the developed world and consumption or handling of contaminated poultry meat is the principal source of infection. Strategies to control Campylobacter in broilers prior to slaughter are urgently required and are predicted to limit the incidence of human campylobacteriosis. Towards this aim, a purified recombinant subunit vaccine based on the superoxide dismutase (SodB) protein of C. jejuni M1 was developed and tested in White Leghorn birds. Birds were vaccinated on the day of hatch and 14 days later with SodB fused to glutathione S-transferase (GST) or purified GST alone. Birds were challenged with C. jejuni M1 at 28 days of age and caecal Campylobacter counts determined at weekly intervals. Across three independent trials, the vaccine induced a statistically significant 1 log10 reduction in caecal Campylobacter numbers in vaccinated birds compared to age-matched GST-vaccinated controls. Significant induction of antigen-specific serum IgY was detected in all vaccinated birds, however the magnitude and timing of SodB-specific IgY did not correlate with lower numbers of C. jejuni. Antibodies from SodB-vaccinated chickens detected the protein in the periplasm and not membrane fractions or on the bacterial surface, suggesting that the protection observed may not be strictly antibody-mediated. SodB may be useful as a constituent of vaccines for control of C. jejuni infection in broiler birds, however modest protection was observed late relative to the life of broiler birds and further studies are required to potentiate the magnitude and timing of protection.

Thermal nociception as a measure of non-steroidal anti-inflammatory drug effectiveness in broiler chickens with articular pain.

Pain associated with poultry lameness is poorly understood. The anti-nociceptive properties of two non-steroidal anti-inflammatory drugs (NSAIDs) were evaluated using threshold testing in combination with an acute inflammatory arthropathy model. Broilers were tested in six groups (n=8 per group). Each group underwent a treatment (saline, meloxicam (3 or 5mg/kg) or carprofen (15 or 25mg/kg)) and a procedure (Induced (arthropathy-induction) or sham (sham-handling)) prior to testing. Induced groups had Freund's complete adjuvant injected intra-articularly into the left intertarsal joint (hock). A ramped thermal stimulus (1°C/s) was applied to the skin of the left metatarsal. Data were analysed using random-intercept multi-level models. Saline-induced birds had a significantly higher skin temperature (± SD) than saline-sham birds (37.6 ± 0.8°C vs. 36.5 ± 0.5°C; Z=-3.47, P<0.001), consistent with an inflammatory response. Saline was associated with significantly lower thermal thresholds (TT) than analgesic treatment (meloxicam: Z=2.72, P=0.007; carprofen: Z=2.58, P=0.010) in induced birds. Saline-induced birds also had significantly lower TT than saline-sham birds (Z=-2.17, P=0.030). This study found direct evidence of an association between inflammatory arthropathies and thermal hyperalgesia, and showed that NSAID treatment maintained baseline thermal sensitivity (via anti-nociception). Quantification of nociceptive responsiveness in a predictable broiler pain model identified thermal anti-hyperalgesic properties of two NSAIDs, which suggested that therapeutically effective treatment was provided at the doses administered. Such validation of analgesic strategies will increase the understanding of pain associated with specific natural broiler lameness types.

Effects of maternal dietary supplementation with three sources of carotenoids on the retinyl esters of egg yolk and developing quail liver.

The effects of supplementation of the maternal diet of quail with three natural sources of carotenoids (alfalfa nutrient concentrate (PX agrotrade mark), tomato powder and marigold extract) on the accumulation of retinol and retinyl esters in egg yolk and in the liver of the new hatchling and maternal were investigated. The present study showed that the vitamin A in quail egg yolk was present in 4 different forms, namely retinol (R 52-62%), retinyl linoleate (RL 9-11%), retinyl stearate (RS 4%), retinyl oleate (RO 11-15%) and retinyl palmitate (RP 13-22%). The retinyl ester profile of the liver of newly hatched quail (R 2-4%, RL 8-12%, RS 19-21%, RO 12-15%, RP 50-55%) differs from that of egg yolk but was similar to that of the liver of adult quail (R 1%, RL 5-6%, RS 21-28%, RO 9-12%, RP 54-63%). It has been shown that RO and RP concentrations in egg yolk and the liver of day old quail chick significantly increased as a result of carotenoid supplementation of the maternal diet.

Protective effect of modified glucomannans against aurofusarin-induced changes in quail egg and embryo.

The aim of this study was to evaluate effects of modified glucomannans (Mycosorb) on egg yolk and liver of the day-old quail after aurofusarin inclusion in the maternal diet. Fifty-four 45-day-old Japanese quail were divided into three groups and were fed ad libitum a corn-soya diet balanced in all nutrients. The diet of the experimental quail was supplemented with aurofusarin at the level of 26.4 mg/kg feed in the form of Fusarium graminearum culture enriched with aurofusarin or with aurofusarin plus Mycosorb at 1 g/kg feed. Eggs obtained after 8 weeks of feeding were analysed and incubated in standard conditions of 37.5 degrees C/55% RH. Samples of quail liver were collected from day-old hatchlings. Main polyunsaturated fatty acids (PUFAs) of the egg yolk were analysed by gas chromatography, and tocopherols and tocotrienols were analysed by HPLC-based methods. Inclusion of aurofusarin in the maternal diet was associated with decreased proportions of docosahexaenoic acid and increased proportions of linoleic acid in major lipid fractions of the egg yolk as well as with decreased concentrations of alpha- and gamma-tocopherols, alpha- and gamma-tocotrienols in egg yolk and liver of a day-old quail. Inclusion of modified glucomannans (Mycosorb) into the quail diet simultaneously with aurofusarin showed a significant protective effect against changes in PUFA and antioxidant composition in the egg yolk and liver of quail. It is suggested that a combination of mycotoxin adsorbents and natural antioxidants could be the next step in counteracting mycotoxins in animal feed.

Antioxidant systems of the developing quail embryo are compromised by mycotoxin aurofusarin.

The effects of aurofusarin in the quail diet on the antioxidant systems of the developing embryo are investigated. Thirty eight 45-day-old Japanese quails (Coturnix japonica) were divided into two groups and were fed on a corn-soya diet or the same diet supplemented with aurofusarin at the level of 26.4 mg/kg feed in the form of Fusarium graminearum culture enriched with aurofusarin. Eggs obtained after 7 weeks of feeding were incubated. Samples of quail tissues were collected at day 17 of embryonic development and from day old hatchlings. Antioxidants and malondialdehyde were analysed by HPLC-based methods. Inclusion of aurofusarin in the maternal diet was associated with decreased concentrations of alpha- and gamma-tocopherols, alpha- and gamma-tocotrienols, retinol, lutein and zeaxanthin in egg yolk. The vitamin E (tocopherols and tocotrienols) concentration in the liver and yolk sac membrane (YSM) of the day 17 embryos and the hatchlings from aurofusarin-fed group was significantly decreased. Alpha-tocopherol concentration was also reduced in kidney, lung, heart, muscle and brain of day-old quails. In the liver of day-old quails, concentrations of lutein, zeaxanthin, retinol, retinyl linoleate, retinyl oleate, retinyl palmitate and retinyl stearate were also reduced. As a result of these diminished antioxidant concentrations, tissue susceptibility to lipid peroxidation was significantly increased. It is suggested that a compromised antioxidant system of the egg yolk and embryonic tissues could predispose quails to increased mortality at late stages of their embryonic development.