Control Birds Research Articles

Effect of active immunization with recombinant-derived goose INH-α, AMH, and PRL fusion protein on broodiness onset and egg production in geese (Anser cygnoides)

This study was conducted to investigate the potential effects of active immunization against recombinant-derived goose inhibin-α (INH-α), anti-Müllerian hormone (AMH), and prolactin (PRL) fusion protein on broodiness onset and egg production in geese. The purified fusion proteins (INH-α, AMH, and PRL) were prepared using a prokaryotic expression system. Female Zhedong geese (10 mo old) were randomly assigned to one of 4 treatments and raised in separate pens. The geese were actively immunized with the recombinant goose INH-α, AMH, or PRL, respectively, and phosphate-buffered saline as control. The results showed the corresponding antibodies were produced when the geese were immune INH-α, AMH-, and PRL-recombinant proteins. The significantly higher luteinizing hormone contents were observed in the INH-α, AMH, and PRL recombinant protein-immunized geese, while the lower AMH hormone content only in PRL-immunized birds. AMH recombinant protein immunized geese had more large yellow follicles of ovary, while the INHα-treated birds with more other follicles compared with control geese. In addition, the geese receiving INH-α recombinant protein, the broodiness onset was about 6 d, which significantly shorter than did PBS immunization (16 d). The INHα- and PRL-immunization also resulted in 12.5 and 8.5 d shorter broody duration intervals compared to the control birds. Moreover, the lower new broodiness rate was observed in three recombinant proteins treated birds. Finally, the PRL recombinant protein-immunization resulted in an average increase of 1.34 eggs during a 40-d observation. Collectively, the data demonstrated that active immunization against recombinant proteins INH-α or AMH could promote LH hormone secretion, regulate follicle development and decrease the broodiness rate. Also, active immunization with a recombinant-derived goose PRL protein might improve egg laying performance.

Pathogenesis of Avian Influenza Virus Subtype H9N2 in Turkeys and Evaluation of Inactivated Vaccine Efficacy.

Avian influenza H9N2 viruses circulate in all types of poultry species, including turkeys, and cause significant losses for the poultry industry in many parts of the word. The aim of this study was to assess the pathogenesis of the Moroccan avian influenza virus (AIV) H9N2 under experimental conditions in turkeys and the protection efficacy of an inactivated commercial vaccine against AIV H9N2. Unvaccinated turkeys showed marked depression sinusitis, respiratory distress characterized by bronchiolar and tracheal rales of moderate severity, and a mortality rate of 50%. Postmortem examinations of dead and euthanatized birds revealed the presence of fibrinous tracheitis and airsacculitis lesions. Vaccination reduced the mortality rate to 20%. Vaccinated birds recovered at day 10 postchallenge, and only 12.5% (1/8) and 37.5% of birds still displayed fibrinous and nonfibrinous airsacculitis lesions, respectively, at day 15 postinoculation. Viral shedding in cloacal and tracheal swabs was lower in vaccinated than in control birds. Although viral RNA was detected in the cloacal swabs of all unvaccinated turkeys at day 3 postinoculation, only 50% of the vaccinated turkeys were positive for virus detection. At day 11 postinoculation, no viral RNA was detected in oropharyngeal swabs of vaccinated turkeys, whereas 40% of the unvaccinated turkeys were still shedding virus.

Discrepancies in the efficacy of H5 inactivated avian influenza vaccines in specific-pathogen-free chickens against challenge with the Egyptian H5N8 clade 2.3.4.4 Group B virus isolated in 2018.

Background and Aim:Highly pathogenic avian influenza H5N8 virus of clade 2.3.4.4 was newly emerged to Egypt and firstly detected in carcasses of wild birds in November 2016. This study assessed the protection efficacy and virus shedding reduction of three different inactivated avian influenza (AI) H5 (H5N1, H5N2, and H5N3) commercial vaccines against challenge with two newly emerging highly pathogenic AI virus H5N8 Egyptian isolates in specific-pathogen-free (SPF) chicks.Materials and Methods:10-day-old SPF chicks (n=260) were divided into 20 groups (n=13). Groups 1-5 were vaccinated through the subcutaneous route (S/C) with 0.5 mL of H5N1 vaccine, Groups 6-10 were vaccinated (S/C) with 0.5 mL of H5N2 vaccine, and Groups 11-15 were vaccinated (S/C) with 0.5 mL of H5N3 vaccine. Positive control groups (16-19) were challenged at 25 and 31 days old (2 and 3 weeks post-vaccination [PV]) using H5N8 clade 2.3.4.4 A/duck/Egypt/F13666A/2017(H5N8) and H5N8 clade 2.3.4.4 A/chicken/Egypt/18FL6/2018(H5N8). Group 20 was left non-vaccinated as a control. All vaccinated groups were divided and challenged with both viruses at 25 and 31 days of age. The viral challenge dose was 0.1 mL of 106 EID50/0.1 mL titer/chick, and it was administered oronasally. All chicks were kept in isolators for 14 days after each challenge. Sera samples were collected weekly and at 2 weeks post-challenge (PC) to detect a humoral immune response. PC mortalities were recorded daily for 10 days to calculate the protection percentages. Tracheal swabs were collected from the challenged chicks in different groups at 3, 5, 7, and 10 days PC. Kidneys and spleens were collected at 3, 5, 7, and 10 days PC and kept in formalin for histopathological examination to assess lesions and severity scores. Tracheal swabs were inoculated in 10-day-old SPF embryonated chicken eggs for virus titration and to calculate shedding levels.Results:All studied vaccines displayed 70-100% protection within 10 days PC. Hemagglutination inhibition results from sera samples revealed antibody titers ranging from 0.6 to 5.4 log2 starting at 1-week PV with the highest titers at 4 weeks PV. Challenged SPF chickens exhibited a notable reduction in virus shedding, with an average of 1.5-2 log10, compared to control birds. Various histopathological lesions with different scores were detected.Conclusion:Our findings suggest that the inadequate virus shedding reduction and protection efficacy of studied vaccines were variable and that the type of vaccine to be used under field conditions should be reconsidered. Study of the variability between the Egyptian old emerged AI (AIV) 2017 H5N8 strains and the new emerging AIV 2018 H5N8 is required to achieve optimal protection and limit the current economic losses.

Rearing enrichments differentially modified hen personality traits and reduced prediction of range use

Domestic fowl have been demonstrated to individually differ in personality, dictating reactions to environmental stimuli. Free-range chickens, Gallus gallus domesticus , show individual range use variation, which may be related to personality differences. Enrichment can also modify behavioural traits. This study measured behavioural impacts of rearing enrichments across pullets and young adults, testing for personality differences and whether they predicted range use variation. Laying hens were reared for 16 weeks across nine pens under three conditions comparing control floor litter rearing with two enrichment types (novel objects or perching structures). At 16 weeks of age, 1386 pullets were transferred to a laying facility, housed in nine identical pens and given range access at 25 weeks. A sample of birds were tested at 9–11 weeks and 20–21 weeks with a series of tests: novel arena, adaptation to the arena with food present, open field, novel maze arena training with food and maze tests. Individual range use from 27 to 31 weeks was measured via radiofrequency identification technology. Enriched pullets were significantly quicker to first step in the adaptation with food present and structurally reared hens were significantly quicker to first step in the open field during testing, but there were no significant differences observed during maze arena training and testing. Of 16 correlations among test parameters, 11 were significant for control birds and six to seven were significant for the enriched treatments. Test parameter and range use correlations were significant for the control birds only. These results support the presence of different personalities in hens with enrichment reducing fear and increasing adaptation. Fewer correlations in the enriched hens suggest they developed a more plastic personality type. This response strategy may have fitness benefits for free-range birds or other captive-reared animals that undergo drastic environmental change across their lifetime. • Behavioural tests were conducted across pullet and adult laying hens. • Rearing enrichments reduced fear and increased adaptation in some tests. • Individual personality variation was confirmed across time. • Rearing enrichments reduced correlations among test parameters. • Test parameters predicted range use in control hens only.

Blood Plasma Biomarkers for Woody Breast Disease in Commercial Broilers.

Woody breast (WB) myopathy results in poor muscle quality. The increasing incidence of WB over the last several years indicates a need for improved prediction or early diagnosis. We hypothesized that the use of body fluids, including blood, may be more suitable than breast muscle tissue in developing a minimally invasive diagnostic tool for WB detection. To identify potential early-age-biomarkers that may represent the potential onset of WB, blood samples were collected from 100, 4 wks old commercial male broilers. At 8 wks of age, WB conditions were scored by manual palpation. A total of 32 blood plasma samples (eight for each group of WB and non-WB control birds at two time points, 4 wks and 8 wks) were subjected to shotgun proteomics and untargeted metabolomics to identify differentially abundant plasma proteins and metabolites in WB broilers compared to non-WB control (Con) broilers. From the proteomics assay, 25 and 16 plasma proteins were differentially abundant (p < 0.05) in the 4 and 8 wks old samples, respectively, in WB compared with Con broilers. Of those, FRA10A associated CGG repeat 1 (FRAG10AC1) showed >2-fold higher abundance in WB compared with controls. In the 8 wks old broilers, 4 and 12 plasma proteins displayed higher and lower abundances, respectively, in WB compared with controls. Myosin heavy chain 9 (MYH9) and lipopolysaccharide binding protein (LBP) showed more than 2-fold higher abundances in WB compared with controls, while transferrin (TF) and complement C1s (C1S) showed more than 2-fold lower abundances compared with controls. From the untargeted metabolomics assay, 33 and 19 plasma metabolites were differentially abundant in birds at 4 and 8 wks of age, respectively, in WB compared with controls. In 4 wks old broilers, plasma 3-hydroxybutyric acid (3-HB) and raffinose concentrations showed the highest and lowest fold changes, respectively, in WB compared with controls. The blood plasma 3-HB and raffinose concentrations were confirmed with targeted biochemical assays. Blood biomarkers, such as 3-HB and raffinose, may be suitable candidate targets in the prediction of WB onset at early ages.

Heat Stress and Feed Restriction Distinctly Affect Performance, Carcass and Meat Yield, Intestinal Integrity, and Inflammatory (Chemo)Cytokines in Broiler Chickens

This study was conducted to distinguish the effects of heat stress (HS) and feed intake (FI) on broiler chicken’s physiological responses. Day-old male Cobb 500 broilers (n = 672) were allocated to three treatments: (1) control (CTL): birds raised under normal temperature (23°C) from day 29 to 42; (2) cyclic heat stress (CHS): birds exposed to high temperatures (8 h/day at 35°C; from 9:30 am to 5:30 pm) from day 29 to 42; (3) pair-fed (PF): birds raised under thermoneutral condition but fed the same amount of feed as CHS from day 29 to 42. On day 42, 15 birds/pen were processed, to measure carcass and meat yields. To measure blood parameters and gut integrity (using fluorescein isothiocyanate-dextran), on day 42, CHS birds were sampled before (Pre-CHS) and 2 h after (Post-CHS) the temperature increased. Furthermore, after sampling CTL birds, they were exposed to 2h heat and sampled (acute heat stress, AHS). Data were analyzed using one-way ANOVA (JMP Pro15) and significance between treatments identified by LSD (P < 0.05). BW and relative carcass yield were significantly higher in CTL compared to CHS and PF. Compared to CHS, PF had significantly higher BW and lower relative carcass yield. Breast yield was significantly higher for CTL and PF, while leg quarters and wings yield were significantly lower compared to CHS. Gut barrier integrity was significantly altered in Post-CHS and AHS compared to CTL. mRNA abundances of tumor necrosis factor-α, C-C motif chemokine ligand-20, heat shock protein (HSP)-27, and HSP70 were significantly higher in Post-CHS and AHS compared to CTL. AHS had significantly higher mRNA abundances of CARD domain containing (NLRC)-3 and NLRC5 inflammasomes, and lower superoxide dismutase (SOD)-1 and SOD2 abundance compared with CTL. PF had significantly higher liver weight (% BW) compared to all other groups; while abdominal fat was significantly higher in Pre-CHS compared to CTL, PF, and AHS. Together, these data indicate that the negative effects of HS are partially due to reduced FI. However, the negative effect of HS on gut integrity, average daily gain, feed conversion ratio, and meat yield are direct and independent of the reduced FI during the HS. Thus, warrant investigating the underlying mechanisms in future research.

Effects of Bacillus subtilis on Production Performance, Bone Physiological Property, and Hematology Indexes in Laying Hens.

Simple SummaryDue to breeding for high egg production, laying hens are at great risk for developing osteoporosis. To develop an effective feed additive for reducing the bone damage and associated pain and economic loss has become a critical issue affecting the poultry industry. The aim of this study was to investigate the effects of Bacillus subtills as a feed supplement on production performance and bone pathophysiological characteristics of laying hens. The results showed that Bacillus subtilis increases marketable eggs, protects bone health, changes the distribution of phosphorus between blood and bone, and increases estrogen but decreases interleukin-1 and tumor necrosis factor-α concentrations in blood. Results indicate that Bacillus subtilis can be used as a dietary supplement to increase marketable egg production and bone health of laying hens by inhibiting gut and systemic inflammation via the microbiota-gut-immune and the microbiota-gut-bone axes.This study was to investigate the effects of Bacillus subtilis on production performance and bone pathophysiological characteristics of layers. Twenty-four 48-week-old Lohmann Pink-shell laying hens were randomly divided into two groups: a basic diet (control) and the basic diet mixed with Bacillus subtilis (0.5 g/kg) for a 60-day trial. Statistically, independent-sample t-test was used to assess the treatment differences. The results showed that Bacillus subtilis supplementation improved the percent of marketable eggs (p < 0.05) with reduced numbers of broken and soft-shelled eggs but had no effects on egg weight, height of albumen, yolk color, and Haugh unit (p > 0.05). Bacillus subtilis supplement also elevated maximum load (p = 0.06), maximum stress (p = 0.01), stiffness (p < 0.01), and Young’s modulus (p < 0.01) but suppressed maximum strain (p = 0.06) in the femur. In addition, compared with control birds, phosphorous concentration (p < 0.01) was reduced in serum at day 61 but increased in the femur (p < 0.05) in Bacillus subtilis fed birds. Bacillus subtilis fed birds also had lower magnesium concentrations in both femur (p = 0.04) and feces (p = 0.09). Furthermore, Bacillus subtilis increased plasma estrogen concentration (p = 0.01) and femur TNF receptor superfamily member 11b (OPG) expression (p < 0.05) but reduced plasma IL-1 (p < 0.01) and TNF-α (p < 0.01) concentrations. These results indicate that Bacillus subtilis could be used as a health promotor to reduce overproduction-induced inflammation and associated bone damage and to increase marketable egg production. The data provide evidence for developing a management strategy to use Bacillus subtilis as a feed additive to improve marketable egg production and health and welfare status of laying hens.

The Impact of Effective Microorganisms (EM) on Egg Quality and Laying Performance of Chickens.

Chickens kept under modern production system are very small and contribute less than 2% of eggs and meat production in Ethiopia. In some parts of the country, effective microorganism (EM) has been used as a means of improving egg and meat production. However, there is information gap on the use and effect of EM on egg quality and laying performance of chickens in the local context. This study was conducted in Aksum University's poultry farm located at the main campus in Axum, to evaluate egg laying performance and quality of eggs in layer chickens treated with effective microorganisms in feed and water. In this experiment, 180 pullets of ISA Brown chickens with uniform age and weight were used and managed in a cage system. Chickens were subjected to 4 treatments with 3 replications, and each replication consisted of 15 chickens. Data collection was started at the first egg lay. Data including feed intake, conversion ratio, and age at first laying, laying percentage, and egg quality parameters were collected. Statistical analysis was carried out using JMP. Chickens fed with EM in feed and drinking water had higher egg production percentage. There was a significant difference in egg laying percentage between the treated and control groups (P < 0.001). Eggs from chickens given EM in feed and water were 6% heavier in weight than those from control birds. Lower feed daily intake (115.5 gram) and feed conversion rate (2.05) were achieved in chickens treated with EM in feed and water. Significant improvement on egg quality was revealed in chickens that received EM in feed and water. From this experiment, it can be concluded that the use of EM in feed and water improves egg production in layer chickens and therefore recommended for medium-scale poultry farms in Northern Ethiopia.

Comparative therapeutic efficacies of oral and in-water administered levamisole, piperazine and fenbendazole against experimental Ascaridia galli infection in chickens

Evidence on the current efficacy status of anthelmintics used in the Australian poultry sector is lacking. A controlled trial was conducted to evaluate the efficacy of three commonly used anthelmintics, namely levamisole (LEV), piperazine (PIP) and fenbendazole (FBZ) plus levamisole-piperazine combination (LEV-PIP) against a field strain of A. galli recovered following flock treatment with LEV. A total of 108 A. galli infected cockerels were randomized into nine experimental groups of 12 cockerels each (eight treatments and one untreated control) with each treatment administered by two routes (oral drench or in drinking water). Chickens received label-recommended doses of LEV (28 mg/kg) and PIP (100 mg/kg) while LEV-PIP involved both compounds co-administered at their full individual dose rates. FBZ was tested at two dose rates; 10 mg/kg as a single oral drench or 5 mg/kg in drinking water over 5 days. Anthelmintic efficacies were assessed by worm count reduction (WCR%) and excreta egg count reduction (EECR%) estimated by two methods. Ten days post treatment, the untreated control birds harboured significantly higher worm counts (P < 0.0001) than those in all treatment groups irrespective of the mode drug of application. Oral drenching caused a greater reduction in worm and egg counts (P < 0.05) than medication in drinking water. Based on geometric worm counts the percentage efficacies for the oral drench were 99.1, 96.3, 97.2 and 100 % respectively for LEV, PIP, FBZ and LEV-PIP, and for administration in water 96.4, 93.7, 88.7 and 97.7 % respectively. Efficacies based on EECR% were consistent with WCR% with strong positive linear association between efficacy values. In conclusion, our results demonstrate no evidence of loss of susceptiblity of the test A. galli isolate to both LEV and PIP contrary to our hypothesis. Additional efficacy studies are needed using A. galli isolates sourced from different poultry flocks across Australia.

Algae-based feed ingredient protects intestinal health during Eimeria challenge and alters systemic immune responses with differential outcomes observed during acute feed restriction

Compounds in microalgae-derived feed ingredients in poultry diets may improve intestinal physiology and immunity to protect against damage induced by physiological and pathogen challenges, but mechanisms are examined sparingly. The study objective was to evaluate changes to intestinal morphology, permeability, and systemic immunity in broilers fed a proprietary microalgae ingredient during 2 separate challenge studies. In study 1, two replicate 28 d battery cage trials used 200 Ross 308 broilers each (n = 400) fed a control diet ± 0.175% algae ingredient. Half of the birds were subjected to a 12 h feed restriction challenge and fluorescein isothiocyanate dextran (FITC-D) intestinal permeability assay on d 28. Study 2 used 800 broilers randomly assigned to the same dietary treatments and housed in floor pens for 42 d. At d 14, intestine and spleen samples were collected from 10 birds/ diet. Half of the remainder was orally inoculated with 10X Coccivac-B52 vaccine in a 2 × 2 factorial treatment design (diet and Eimeria inoculation). The FITC-D assay was conducted at 1, 3, 7, and 14 d post-inoculation (pi) while intestinal and spleen samples were collected at 3, 7, 14, and 28 dpi for histomorphology and flow cytometric immune cell assessment. Study 1 validated intestinal leakage via FITC-D absorbance induced by feed restriction but showed no algae-associated protective effects. In study 2, algae preserved intestinal integrity during coccidiosis (P = 0.04) and simultaneously protected jejunal villus height as early as 7dpi (P < 0.0001), whereas intestinal damage resolution in control birds did not occur until 14 dpi. Algae inclusion increased splenic T cells in unchallenged broilers at d 14 by 29.6% vs. control (P < 0.0001), specifically γδ T cell populations, without impacting performance (P < 0.03). During Eimeria challenge, splenic T cells in algae-fed birds did not show evidence of recruitment to peripheral tissues, while control birds showed a 16.7% reduction compared to their uninoculated counterparts from 3 to 7 dpi (P < 0.0001). This evidence suggests the algae ingredient altered the immune response in a manner that reduced recruitment from secondary lymphoid organs in addition to protecting intestinal physiology.

Influence of environmental enrichment on circulating white blood cell counts and behavior of female turkeys

Under commercial conditions turkeys are housed in large groups in poorly structured environments. This leads to stress and subsequently to pecking and cannibalism. Environmental enrichment is suggested to reduce stress and feather pecking, thus leading to an increase of the overall flock health. However, the effect of increasing age on the use of enrichment elements and on the behavior repertoire as well as its correlation with health parameters has scarcely been studied. Therefore, our objective was to investigate the influence of environmental enrichment on the behavioral repertoire and on health parameters of turkeys. In 3 consecutive trials, female turkeys were housed up to 12 wk either in an unstructured (control group) or enriched environment (EE group) featuring elevated plateaus at different levels (“turkey tree”). Behavior parameters, clinical health, and immune parameters were determined at selected time points. The percentage of birds using the turkey tree increased with age up to 55 to 77% at 22 to 30 d post hatch (dph). Thereafter, the number of birds located on the turkey tree decreased to 25 to 32% at 73 to 79 dph. Feather pecking and fighting was significantly lower in the EE group compared to the control group in 2 and 3 trials, respectively (P < 0.05). The integrity of feathers and integument, scored in the head/neck, wing, and tail regions was repeatedly better in the EE birds compared to control birds at most investigated time points (P < 0.05), suggesting a reduction in stress related aggression by the use of the turkey tree. Head pecking, running and flying activity, foraging, and preening were overall comparable between the EE and the control group (P > 0.05). Humoral immunity as determined by vaccination-induced anti-Newcastle disease virus antibody titers was not affected by the turkey tree use. The flow cytometric evaluation of blood monocyte and T-lymphocyte numbers showed no repeatable difference between control and EE groups. Interestingly, compared to the control groups, EE birds displayed significantly higher numbers of circulating MHC class II+ lymphocytes and lower numbers of thrombocytes at various time points compared to controls (P < 0.05). This study provides clear evidence that environmental enrichment with plateaus not only leads to an altered behavioral repertoire but also modifies some of the investigated immune parameters, implying that EE may have a modulatory effect on turkeys’ immunity and overall fitness. Further studies are needed to understand the correlation between behavior and health parameters in birds more closely.

Influence of the Immunomodulator AVIGEN to Broiler Chicken Humoral Immune Factors

The nonspecific immune response plays an important role in organism's defense against a variety of pathogens. Two major factors in this process are blood serum lysozyme and alternative pathway of complement activation (APCA). Over the past few decades, the application of various substances, targeting improved levels of natural immunity have become part of the mainstream trends in livestock rearing programs. The current study examined the influence of the polybacterial immunomodulator AVIGEN on the performance of the aforementioned immune factors among broiler chicken hybrids. The experimental group demonstrated better overall performance for both parameters of interest. APCA activity for the treated group (549.10±19.69 CH50) was significantly higher compared to the result obtained for the controls (377.40±9.58 CH50), (P<0.001). Results for the other parameter were even more indicative. The measured concentration of the serum lysozyme for the treated group was twice as high compared to the control birds - 6.17±0.49 mg/L vs. 2.99±0.27 mg/L, respectively. Therefore, the introduction of the AVIGEN immunomodulator to animals' diet has strong potential to improve natural humoral immunity in poultry farming.

Dietary vitamin E reaches the mitochondria in the flight muscle of zebra finches but only if they exercise.

Whether dietary antioxidants are effective for alleviating oxidative costs associated with energy-demanding life events first requires they are successfully absorbed in the digestive tract and transported to sites associated with reactive species production (e.g. the mitochondria). Flying birds are under high energy and oxidative demands, and although birds commonly ingest dietary antioxidants in the wild, the bioavailability of these consumed antioxidants is poorly understood. We show for the first time that an ingested lipophilic antioxidant, α-tocopherol, reached the mitochondria in the flight muscles of a songbird but only if they regularly exercise (60 min of perch-to-perch flights two times in a day or 8.5 km day-1). Deuterated α-tocopherol was found in the blood of exercise-trained zebra finches within 6.5 hrs and in isolated mitochondria from pectoral muscle within 22.5 hrs, but never reached the mitochondria in caged sedentary control birds. This rapid pace (within a day) and extent of metabolic routing of a dietary antioxidant to muscle mitochondria means that daily consumption of such dietary sources can help to pay the inevitable oxidative costs of flight muscle metabolism, but only when combined with regular exercise.

Effects of dietary energy level and guanidino acetic acid supplementation on growth performance, carcass quality and intestinal architecture of broilers

Energy, known as the most expensive nutrient in broiler feed, is what strongly adjusts and affects the growth of broilers. Creatine has a key role in cellular energy metabolism and could be synthesised from guanidinoacetic acid (GAA) in the liver; however, its de novo synthesis is not able to adequately fulfil the demand of energy metabolism, especially in fast-growing modern broilers. So the aim of the study was to evaluate the efficiency of commercial GAA in energy-reduced broiler diets on performance and intestinal development. Overall, 11 400 day-old Ross 308 chicks were randomly allocated to six dietary treatments with ten replicates in each. Dietary treatments were designed as a 3 × 2 factorial arrangement with three levels of dietary metabolisable energy (AME&lt;sub&gt;n&lt;/sub&gt;) recommended by Aviagen for Ross 308 broilers (12.55 MJ/kg, 12.97 MJ/kg and 13.38 MJ/kg for starter, grower and finisher, respectively), 0.209 MJ/kg and 0.418 MJ/kg reduced and two levels of GAA (0.00% and 0.06%). There was no significant GAA × AME&lt;sub&gt;n&lt;/sub&gt; interaction for all performance parameters, carcass traits and jejunal morphological parameters (except for the villus width). Reduction of dietary AME&lt;sub&gt;n&lt;/sub&gt; (0.209 MJ/kg and/or 0.418 MJ/kg) caused a significant depression in body weight (BW) gain (P &amp;lt; 0.001) and feed conversion ratio (FCR) (P &amp;lt; 0.001). However, a decreasing AME&lt;sub&gt;n&lt;/sub&gt; level increased villus height (P &amp;lt; 0.003) and villus surface area (P &amp;lt; 0.03), while crypt depth and villus width were similar. The GAA improved final BW and FCR by 1.77% and 1.66%, respectively (P &amp;lt; 0.001). Birds fed low energy diets supplemented with GAA showed a significant improvement in the performance so that BW and FCR were the same as in the control birds; however, no such positive effects were obtained in jejunal villus development. Hence, it might be concluded that 0.06% GAA supplementation improves BW and FCR and can save at least 0.209 MJ/kg dietary AME&lt;sub&gt;n&lt;/sub&gt; in broiler diets.

Time-Restricted Feeding in Commercial Layer Chickens Improves Egg Quality in Old Age and Points to Lack of Adipostat Activity in Chickens.

In mammals, time-restricted feeding (TRF) with no caloric restriction provides health benefits and extends longevity, usually with a minor (∼3%) or no reduction in total food consumption. In the current study, a TRF regimen of 6 h free access to food (08:00–14:00 h) was applied to Leghorn chickens from 25 to 86 weeks of age; control birds ate freely during the light hours (06:00–20:00 h). Unexpectedly, the TRF-treated birds consumed, on average, 11.7% less food than the controls. This was manifested by an average reduction of 9.6% in body weight, 2.6-fold in visceral fat accumulation, and 6.5% in egg weight. Hen-housed egg production was reduced by 3.6% in the TRF group compared with the control, along the first 40 weeks of the follow-up (P < 0.05), and changed into a tendency of 0.7% higher egg production thereafter. Several parameters of egg quality showed significant improvement (P < 0.05) in the TRF group compared with the controls. A comparison of diurnal patterns of feed consumption revealed a higher rate of hourly consumption in the TRF group and increased consumption before dark in the control group. In conclusion, the reduced feed intake in response to the TRF treatment and loss in visceral fat accumulation supports the lack of a strong adipostat activity in chickens and different appetite regulation mechanisms compared with mammals. Therefore, future TRF studies in chickens should be adjusted by extending the ad libitum time window. The lower feed intake by the TRF-treated chickens compared with the ad libitum-fed controls seems to reduce the efficiency of egg production. Nevertheless, the improved egg quality and persistence of egg lay at the older age suggest that similarly to mammals, the TRF treatment delayed at least some of the negative impacts associated with advanced age.

No effect of passive integrated transponder tagging method on survival or body condition in a northern population of Black-capped Chickadees (Poecile atricapillus).

Passive integrated transponder (PIT) tags allow a range of individual‐level data to be collected passively and have become a commonly used technology in many avian studies. Although the potential adverse effects of PIT tags have been evaluated in several species, explicit investigations of their impacts on small (<12 g) birds are limited. This is important, because it is reasonable to expect that smaller birds could be impacted more strongly by application of PIT tags. In this study, we individually marked Black‐capped Chickadees (Poecile atricapillus), a small (circa 10 g) passerine, at the University of Alberta Botanic Garden to evaluate potential lethal and sublethal effects of two PIT tagging methods: attachment to leg bands or subcutaneous implantation. We used a Cox proportional hazards model to compare the apparent survival of chickadees with leg band (N = 79) and implanted PIT tags (N = 77) compared with control birds that received no PIT tags (N = 76) over the subsequent 2 years based on mist net recaptures. We used radio‐frequency identification (RFID) redetections of leg band PIT tags to evaluate sex‐specific survival and increase the accuracy of our survival estimates. We also used a generalized linear regression model to compare the body condition of birds recaptured after overwintering with leg band PIT tags, implanted PIT tags, or neither. Our analysis found no evidence for adverse effects of either PIT tagging method on survival or body condition. While we recommend carefully monitoring study animals and evaluating the efficacy of different PIT tagging methods, we have shown that both leg band and subcutaneously implanted PIT tags ethical means of obtaining individualized information in a small passerine.

Induction of reproductive activity and egg production by gonadotropin-releasing hormone in non-laying hens.

The current study was conducted to evaluate the effects of gonadotropin-releasing hormone (GnRH) analogue (Receptal) injection on reproductive traits of fully mature layers hens (32weeks) suffered from inactive ovaries. Ninety-six non-laying hens (TETRA-SL brown egg layers), selected from a commercial flock, with similar body weight, were randomly assigned to four groups (n=24). Hens in the 1st group served as a control. Hens of the 2nd, 3rd and 4th groups were individually intramuscularly injected every 4days with 50, 100 and 150µl of Receptal solution, respectively, for two times. The results stated that the injection of Receptal induced the non-laying hens to produce eggs, but control birds did not produce eggs during the experimental period. The distance between pelvic bones and between the pelvic bone and keel bone of hens was significantly improved (p<.001) in groups received different GnRH levels compared with the control group. The best results were observed in the group injected with 100µl Receptal. Levels of LH, FSH, oestrogen and progesterone hormones were significantly (p<.05) higher in Receptal-treated groups than in the control group. Hens injected with Receptal had an increase in ovary%, yellow follicles number, oviduct% and oviduct length (p<.001) compared with the control. It was concluded that treating inactive ovaries in non-laying hens with GnRH injections for two times, 4-day intervals, is an effective procedure for inducing egg production and useful in cost reduction in layer farms, and the group treated with 100µl Receptal had the best results.

Haematology and hormonal assay of heat-stressed broiler chickens managed by feather clipping and ascorbic acid supplementation

Introduction: High ambient temperature (HAT) induces stress in birds and affects their wellbeing. This study investigated the haematology and serum levels of corticosterone, triiodothyronine and thyroxine of heat-stressed broilers managed by feather clipping (FC) and ascorbic acid (AA) supplementation. Methods: One hundred Anak broiler chicks were distributed into five treatments of 20 chicks each in 2 replicates and were all fed basal diets. The positive control (PC) birds were intact (not feather clipped) and managed under controlled (28 – 30℃) environment. Other groups were managed in open pen under HAT (43.0 ± 2.0℃). The negative control (NC) birds were intact. The treatment 1(T1) birds were feather-clipped, the treatment 2 (T2) groups were intact, together with 200 mg AA/kg feed supplemented while the treatment 3 (T3) birds were feather-clipped and fed with 200mg AA supplemented feed. Data were analysed using ANOVA. Results: The results showed that feather clipping and AA supplementation did not affect blood parameters of the birds except white blood cell count and heterophil-lymphocyte ratio. The levels of the three hormones differed significantly (P &lt;0.05) in the PC group compared to HAT-exposed groups. Corticosterone levels decreased in T1 (8.20 ng/mL) and T3 (7.99 ng/mL) significantly against 9.70 ng/mL in NC, the lowest value of 7.88 ng/mL was recorded in PC. Triiodothyronine (4.04 ng/mL) and thyroxine (11.29 ng/mL) levels were highest in PC, lowest triiodothyronine (2.78 ng/mL) and thyroxine (7.97 ng/mL) concentrations were recorded in NC and T1 groups respectively. Significance: Therefore, feather clipping and/or AA supplementation ameliorated adverse effect of extreme heat in the broiler chickens.

Effects of Olive, Milk Thistle, and Artichoke Extracts on Performance, Biochemical and Enzymatic Changes in Carbon Tetrachloride-intoxicated Broiler Chickens

This study was conducted to examine the effects of olive, milk thistle, and artichoke extracts on growth performance, biochemical and enzymatic changes in birds intoxicated with CCl4 (at 0.5, 0.75, and 1 mL/kg body weight in days 14, 21, and 28 of age, respectively). Two hundred twenty-five 10-day-old Ross 308 female broiler chicks were used in a completely randomized block design to evaluate the effects of five treatments consisting 1) a basal diet given to the birds injected intraperitoneally with 0.5 mL saline (control-), 2) The same basal diet given to birds injected intraperitoneally with CCl4 (control+), 3, 4, and 5) The basal diet supplemented with either 400 mg/kg milk thistle, olive extracts, or artichoke extract given to the birds injected with CCl4. Dietary Supplementation of each herbal extract increased feed intake compared with the control birds (P < 0.05). The broilers fed on the artichoke supplemented diet showed a greater serum concentration of HDL-c than other birds on day 28 of age (P < 0.05). Feeding the control diet to the CCl4 injected birds and the olive extract-included diet with no injection resulted in a greater serum alanine aminotransferase concentration at day 42 of age (P < 0.05). Serum malondialdehyde concentration decreased in the birds given the control diets (P < 0.05). The supplementary olive extract increased serum concentrations of malondialdehyde and total anti-oxidant on day 42 of age (P < 0.05). Liver health score improved in the broilers grown on the herbal extract-added diets (P < 0.05). In conclusion, administration of olive, milk thistle, and artichoke extracts promoted feed intake and exerted a potentially positive role as an antioxidant in liver health as evidenced by certain promising changes in serum biochemistry and enzyme activity as well as liver health score.

Effect of Adding Watermelon Juice, Vitamin E-Selenium, and Vitamin C into the Drinking Water on Growth Performance, Internal Organs’ weight and Prececal Nutrient Digestibility in Broilers under Heat Stress

This study investigated the effect of adding watermelon juice, vitamin Eselenium and vitamin C to the drinking water on growth performance, internal organs’ weight, and prececal nutrient digestibility in broilers under heat stress. Two hundred and fifty Hubbard F15 day-old broilers were allocated to five treatments with five replicates of 10 broilers per each replicate, based on a completely randomized design. The birds in the control treatment did not receive any supplement in drinking water and reared in thermoneutral temperature. Birds in the other four treatments received watermelon juice at 60% or 30%, vitamin C at 50 mg/L, or vitamin E-Selenium at 1 mL/L of drinking water during the heat stress period. Heat stress applied for 9 hours from day 12 onward. Results indicated birds that received 60% watermelon juice had similar body weight and feed intake compared to control birds. The relative weight of proventriculus, intestine length, and prececal dry matter nutrient digestibility was significantly higher in 60% watermelon juice treatment than other treatments. It is concluded that watermelon juice supplementation at 60% concentration into the drinking water could improve the performance of birds reared under heat stress as a result of restoring water and feed intake and also better prececal dry matter digestibility.