Control Birds Research Articles

Effects of bioactive peptides derived from feather keratin on plasma cholesterol level, lipid oxidation of meat, and performance of broiler chicks.

In this research, the effect of mixed feather bioactive peptides (MFBPs) added in water, on intestinal health, meat quality, and plasma cholesterol level of broiler chickens, was evaluated. A total of 80day-old male broiler chicks (Ross 308) were randomly divided into two treatments with four replication pens. The dietary treatments were the drinking water with no additives (control) and drinking water containing 50mg/L of MFBPs. Live weight and feed intake were measured at the end of starter (1-10days), grower (11-24days), and finisher (25-36days) periods by calculating the average daily gain and feed conversion ratio. The results indicate that body weight gain was greater (P < 0.05) in birds that received MFBPs in the final period. At 24days of age, the villus height and muscle layer thickness in different parts of the intestine were higher in birds that received bioactive peptides but epithelial thickness was lower than that in control birds (P < 0.05). In addition, the administration of MFBPs decreased (P < 0.01) serum total cholesterol, triglyceride, and low-density lipoprotein in broilers. Supplementation with MFBPs significantly reduced (P < 0.01) the malondialdehyde (MDA) amount in the thigh muscle. In conclusion, using the MFBPs in the diet of broilers could improve meat quality, cholesterol concentration in serum, and gut health.

Ascaridia galli eggs obtained from fresh excreta, worm uteri or worms cultured in artificial media differ in embryonation capacity and infectivity

Ascaridia galli infection models use eggs isolated from chicken excreta, worm uteri and worms cultured in artificial media. The aim of this study was to compare the infectivity of A. galli eggs isolated from these sources under two infection regimens. A 3 × 2 factorial arrangement was employed to test the infectivity of A. galli eggs from the three sources and two modes of infection (single or trickle infection). One hundred and fifty-six Isa-Brown one day-old cockerels randomly assigned to the six treatment groups (n = 26) were orally infected with embryonated A. galli eggs obtained from the three A. galli egg sources (worm uteri, excreta or eggs shed in vitro) administered either as single dose of 300 eggs at one day-old or trickle infected with 3 doses of 100 eggs over the first week of life. Twenty-two negative control birds remained uninfected. Eggs obtained from cultured worms or excreta exhibited a higher embryonation capacity (P = 0.003) than eggs obtained from worm uteri. There were higher worm establishment (infectivity) rates from embryonated eggs originating from cultured worms and worm uteri compared with eggs obtained from fresh excreta (P < 0.0001). Trickle infection resulted in a significantly higher total worm burden (P = 0.002), establishment rate (P = 0.002) and excreta egg counts (EEC, P = 0.025) than single infection. Worm length was greater in birds infected with embryonated eggs from excreta than from uteri or cultured worms (P < 0.0001). However, mode of infection did not affect worm length (P = 0.719) and weight (P = 0.945). A strong significant positive linear correlation was observed between EECs and female worm counts at 12 weeks of post infection sampling (r = 0.75; P < 0.0001). Body weight of birds was negatively correlated with both worm burden (r = − 0.21; P < 0.01) and EEC (r = − 0.20; P < 0.05) at 12 weeks post infection. In conclusion, our results show that eggs shed by cultured worms or isolated from worm uteri had greater infective capacity than eggs harvested from excreta and that trickle rather than bolus infection resulted in higher worm establishment. These factors should be taken into account when considering artificial infection protocols for A. galli.

Clinicopathologic Findings in Chickens (Gallus gallus domesticus) Administered Amikacin Through Intravenous Regional Limb Perfusion.

Regional limb perfusion (RLP) has been used to treat cases of distal limb infections in avian species. Potentially nephrotoxic drugs, such as amikacin, may increase the risk of nephrotoxicity with RLP because of the presence of the renal portal system and direct venous blood flow from the pelvic limbs to the kidneys. In a randomized, blinded, placebo-controlled study, the safety of repeated amikacin administration (20 mg/kg q24h for 3 doses) via RLP was evaluated in healthy female chickens (Gallus gallus domesticus; n = 8 treatment, n = 8 saline control group). Plasma uric acid concentrations were not significantly elevated in treated birds compared with the control group at any time point following RLP. One week following the final RLP, birds were necropsied and the kidneys evaluated grossly and histologically. There was no significant difference in renal pathology scores between treated and control birds or between kidneys ipsilateral to the perfused limb and contralateral kidneys. This study concludes that RLP of amikacin at high doses produced no discernable renal pathology in healthy euhydrated chickens.

Lung infection of avian pathogenic Escherichia coli co-upregulates the expression of cSP-A and cLL in chickens

The host innate defense–pathogen interaction in the lung has always been a topic of concern. The respiratory tract is a common entry route for Avian pathogenic Escherichia coli (APEC). Chicken surfactant protein A (cSP-A) and chicken lung lectin (cLL) can bind to the carbohydrate moieties of various microorganisms. Despite their detection in chickens, their role in the innate immune response is largely unknown. This study aimed to examine whether the expression levels of cSP-A and cLL in the chicken respiratory system were affected by APEC infection. A lung colonization model was established in vivo using 5-day-old specific-pathogen-free chickens infected intratracheally with APEC. The chickens were euthanized 12 h post-infection (hpi) and 1–3 days post-infection (dpi) to detect various indicators. The results of quantitative reverse transcription-polymerase chain reaction and fluorescence multiplex immunohistochemical staining showed that the mRNA and protein expression levels of cSP-A and cLL in the lung and trachea were significantly co-upregulated at 2dpi.Transcriptome RNA-sequencing analysis indicated that the inoculation with APEC AE17 at 2 dpi resulted in differential gene expression of approximately 810 genes compared with control birds, but only a few genes were expressed with astatistically significant ≧2-fold difference. cLL and cSP-A were among the significantly upregulated genes involved in innate immunity. These findings indicated that cSP-A and cLL might play an important role in lung innate host defense against APEC infection at the early stage.

Evaluation of weight-bearing, locomotion, thermal antinociception, and footpad size in a carrageenan-induced inflammatory model in the cockatiel (Nymphicus hollandicus).

To evaluate a carrageenan-induced inflammatory model in the cockatiel (Nymphicus hollandicus) using weight-bearing load, rotational perch locomotion, thermal threshold withdrawal, and footpad dimensions. 16 adult cockatiels (8 males and 8 females). Cockatiels were randomly assigned into 2 groups as either treatment (carrageenan injection; n = 8) or control (handling only; 8). Treatment of cockatiels involved unilateral subcutaneous injection of 0.05 mL of 1% lambda carrageenan solution into the left footpad. Control birds were handled in a similar manner without an injection. Following baseline measurements and treatment or control procedures, posttreatment measurements at multiple time points involving weight-bearing perch load (for up to 336 hours), locomotive abilities when placed on a rotating perch (for up to 96 hours), thermal withdrawal threshold (for the 24- to 30-hour period), and both vertical and horizontal left footpad size and degree of swelling (for up to 84 days) were obtained. Treatment cockatiels had a significant decrease in left foot weight-bearing load and increase in left footpad dimensions and swelling grade over time compared to control cockatiels. Rotational perch locomotion and thermal withdrawal threshold, conversely, did not differ significantly between groups. Cockatiels injected with carrageenan returned to normal weight-bearing within 2 weeks; however, left footpad dimensions did not return to baseline. Carrageenan footpad injection prompts a measurable and grossly visible inflammatory response in the cockatiel. Additionally, it induces alterations in weight-bearing distribution in injected birds. This model provides a method to evaluate inflammation and lameness in small psittacine species.

THE EFFECT OF DEXAMETHASONE ON HEMATOLOGIC PROFILES, HEMOSPORIDIAN INFECTION, AND SPLENIC HISTOLOGY IN HOUSE FINCHES (HAEMORHOUS MEXICANUS).

Research on host response to infectious disease often involves pharmacological induction of immunosuppression, frequently through administration of dexamethasone. Reports on the effect of dexamethasone in birds are largely restricted to poultry and pigeons. This study describes changes in white blood cell (WBC) differentials, hemoparasite counts, splenic histology, and splenic CD3 immunoreactivity in House Finches (Haemorhous mexicanus). Experimental group birds (n=9) were treated with a daily intramuscular injection of 25 µg of dexamethasone for 8 d; a control group (n=9) received daily saline solution. Smears were made with blood collected immediately before the first dose (day 0) and on d 4, 8, and 9, and stained with modified Wright. The WBC differential counts were performed by three blinded observers, parasite counts by two blinded observers, and histology by one blinded observer. Dexamethasone-treated birds experienced relative heterophilia and lymphopenia on d 4 (P=0.008); heterophilia was also present at d 8 (P=0.018). Hemosporidian counts were significantly increased in dexamethasone-treated birds on d 4 and 8 (P=0.048 and P=0.031, respectively). In contrast with control birds, all dexamethasone-treated birds lacked histologically apparent splenic lymphoid follicles (P<0.001). No significant difference was observed in splenic CD3 immunoreactivity between groups. Our results indicate that dexamethasone has an effect on the hematologic profile of House Finches and suggest that it may be a useful method to induce immunosuppression in this species.

Areca catechu L. and Anredera cordifolia (Ten) Steenis supplementation reduces faecal parasites and improves caecal histopathology in laying hens

ABSTRACT Some studies have shown that the betel nut Areca catechu L and “binahong” leaves Anredera cordifolia (Ten) Steenis have anti-parasite and wound healing properties. This study evaluated the effect of A. catechu nut and A. cordifolia leaves powder supplementation on faecal parasite number and type, histopathology of the intestine, caecum, associated organs, some serum biochemistry, and egg production of laying hens. Twenty-four 54-week-old ISA-brown laying hens from local layer farmers were assigned randomly into 4-treatment groups: 1) without supplementation (T0), 2) supplemented with 0.25% (T0.25%), 3) 0.5% (T0.5%), 4) 1.0% (T1.0%). We carried out the supplementation for 18 days by administering A. catechu nut powder for 3-days, and subsequently, A. cordifolia leaves powder for another 3-days for 3-rounds to control the parasite larvae. Faecal parasite count and type were enumerated at the beginning and end of treatment. Egg production was recorded daily during the 18 days experiment. Blood was sampled at the end of the experiment to determine serum albumin, globulin, and transaminases. The intestinal tract, liver, and spleen samples were collected at the end of the study for histopathological examination. Faecal Ascaridia galli in control hens increased by 87.5% after 18 days of the experiment, while A. catechu nut and A. cordifolia leaves powder supplementation prevented such an increase. Supplemented hens have a better reduction of Railentina cesticillus compared to control birds. Supplementation improved intestinal and other tissue histopathology, especially in the caecum (free of erosion), improving serum albumin and transaminases without affecting egg production.

Performance comparison of homologous and heterologous Newcastle disease virus in vaccines and antibody tests

Antigenic differences between commercial Newcastle Disease Virus (NDV) vaccine and circulating field virus reduce vaccine efficacy. Fifty-layer chickens were divided into five groups: three vaccinated chicken groups using killed LaSota (Genotype II/GII), Mega, or VD (Genotype VII/GVII) viral strains, negative, and positive control groups. On day 28, Hemagglutination Inhibition (HI) serology of vaccinated chickens was performed using whole virus antigens of RIVS, LaSota, Mega, and VD strains. Sera were also tested with an alternative antigen, using an ELISA to detect antibody for the cleavage site F protein peptide from GII and GVII NDV strains. Vaccinated and unvaccinated positive control birds underwent infectious challenges using VD and Mega strains. HI testing showed that antibody titers were higher when tested using homologous antigens than heterologous antigens. ELISA performed with alternative antigens did not perform as well as the established HI test using homologous strains. Viral shedding was reduced by vaccination that was homologous to the infectious challenge in comparison with vaccination using the LaSota strain virus. We conclude that superior results are obtained when serological testing, vaccinations, and vaccine challenge experiments all use circulating strains of ND virus. Implementation of this recommendation would likely reduce viral shedding by vaccinated chickens and be more effective in preventing outbreaks of virulent NDV.

Corticosterone Alters Body Weight, but Not Metabolites, during Chronic Stress

AbstractThe stress response is partially mediated by increased levels of circulating glucocorticoids. While the stress response may be adaptive in the short term, chronically elevated levels of glucocorticoids can be pathological. We aimed to verify that chronic stress causes metabolic dysregulation via increased corticosterone (Cort) exposure by monitoring free fatty acid (FFA) concentrations (evidence of fat breakdown), uric acid concentrations (evidence of protein breakdown), and organ weights (furcular fat, abdominal fat, liver, and pectoralis muscle) in chronically stressed juvenile house sparrows (Passer domesticus). The sparrows were chronically stressed for 3 wk by applying a series of rotating mild psychological stressors. One group of birds received injections of a glucocorticoid steroidogenesis inhibitor (mitotane) and a second group received injections of a glucocorticoid receptor antagonist (RU486) halfway through the chronic stress period to test whether glucocorticoids are responsible for protein and fat catabolism during chronic stress. Toward the end of the chronic stress period, mitotane birds increased weight compared to control and RU486 birds. Contrary to expectations, we saw no differences in FFA or uric acid levels between control and mitotane birds, but RU486 temporarily decreased stress-induced uric acid levels. Neither mitotane nor RU486 significantly altered organ weights at the end of the 3 wk. In conclusion, Cort does appear to negatively affect body weight, but the mechanism does not appear to involve increased protein or lipid metabolism.

Protective efficacy of an H5/H7 trivalent inactivated vaccine (H5-Re13, H5-Re14, and H7-Re4 strains) in chickens, ducks, and geese against newly detected H5N1, H5N6, H5N8, and H7N9 viruses

Some H5 viruses isolated in poultry or wild birds between 2020 and 2021 were found to be antigenically different from the vaccine strains (H5-Re11 and H5-Re12) used in China. In this study, we generated three new recombinant vaccine seed viruses by using reverse genetics and used them for vaccine production. The vaccine strain H5-Re13 contains the hemagglutinin (HA) and neuraminidase (NA) genes of an H5N6 virus that bears the clade 2.3.4.4h HA gene, H5-Re14 contains the HA and NA genes of an H5N8 virus that bears the clade 2.3.4.4b HA gene, and H7-Re4 contains the HA and NA genes of H7N9 virus detected in 2021. We evaluated the protective efficacy of the novel H5/H7 trivalent inactivated vaccine in chickens, ducks, and geese. The inactivated vaccine was immunogenic and induced substantial antibody responses in the birds tested. Three weeks after vaccination, chickens were challenged with five different viruses detected in 2020 and 2021: three viruses (an H5N1 virus, an H5N6 virus, and an H5N8 virus) bearing the clade 2.3.4.4b HA gene, an H5N6 virus bearing the clade 2.3.4.4h HA gene, and an H7N9 virus. All of the control birds shed high titers of virus and died within 4 days post-challenge, whereas the vaccinated chickens were completely protected from these viruses. Similar protective efficacy against H5 viruses bearing the clade 2.3.4.4h or 2.3.4.4b HA gene was observed in ducks and geese. Our study indicates that the newly updated H5/H7 vaccine can provide solid protection against the H5 and H7N9 viruses that are currently circulating in nature.

Alterations in connexin 43 gene and protein expression in the chicken oviduct following tamoxifen treatment

Connexins (Cxs) are a group of gap junction proteins involved in the direct exchange of small molecules between neighboring cells. Information concerning the expression and regulation of Cxs in the chicken oviduct is lacking, but likely has potential implications for functioning of the oviduct and the quality of the egg laid by commercially used hens. The present study was designed to examine whether selected Cxs are present in the chicken oviduct and, if so, whether expression of the most abundant Cx changes following tamoxifen (TMX; estrogen receptor modulator) treatment. Hy-Line Brown laying hens were injected (s.c.) daily with a vehicle (n = 6) or with TMX (n = 6), at a dose of 6 mg/kg of body weight for 7 days until complete cessation of egg laying by TMX-treated hens. All oviductal segments (infundibulum, magnum, isthmus, shell gland, and vagina) were collected from hens on day 8 of the experiment. First, the gene expression of GJA1 (i.e. Cx43 protein), GJA4 (Cx39), GJB1 (Cx32), and GJD2 (Cx36) was investigated by real-time PCR in tissues of control birds. The results demonstrated gene- and oviductal segment-dependent expression of GJB1, GJD2, GJA4, and GJA1 mRNA. Since the GJA1 transcript was the most abundant in all oviductal parts, subsequently, the Cx43 expression and localization were examined in the oviduct of all hens. The relative expression of GJA1 mRNA in control hens was highest in the infundibulum and vagina and lowest in the magnum. The pattern of Cx43 protein abundance evaluated by Western blot was similar to that of mRNA. Treatment of hens with TMX decreased the GJA1 mRNA levels in the magnum and isthmus, and Cx43 protein abundances were reduced in the isthmus and vagina. Immunofluorescence demonstrated cell- and segment-dependent localization of Cx43 protein in the oviductal wall; the most intense immunoreactivity was observed in the muscle cells of the shell gland and vagina. In TMX-treated hens, the immunoreactivity for Cx43 in all oviductal segments was slightly reduced and had a different signal pattern compared with control chickens. These results suggest that Cx43 likely takes part in the regulation of oviduct functioning, especially in the coordination of muscle contraction required for egg transport and oviposition. In addition, the results suggest a contribution of estrogen in the regulation of Cx43 expression and/or fates in the chicken oviduct. New insights into the expression and regulation of Cxs in the hen oviduct, indicating their potential involvement in the mechanisms of egg formation and transport that may affect poultry production, were obtained in this study.

Milk Thistle (Silybum marianum), Marine Algae (Spirulina platensis) and Toxin Binder Powders in the Diets of Broiler Chickens Exposed to Aflatoxin-B1: Growth Performance, Humoral Immune Response and Cecal Microbiota

This research was performed to investigate the effects of milk thistle (MT), toxin binder (TB) and marine algae (Spirulina platensis; SP) on the performance, blood indices, humoral immunity and cecal microbiota of broiler chickens exposed to aflatoxin-B1 (AFB1). A total of 300 one-day-old male chicks were equally divided into five treatments, with six replicates with 10 birds per treatment. Dietary treatments included: (T1) a control diet (without any feed additive or AFB1); (T2) control diet + 0.6 mg AFB1/kg; (T3) T2 + 10 g/kg MT; (T4) T2 + 1 g/kg TB; and (T5) T2 + 10 g/kg SP. BWG and FI were found to be considerably reduced in broilers given AFB1-contaminated diets (p &lt; 0.05). The FCR was negatively influenced in birds fed AFB1-contaminated diets (p &lt; 0.05). MT, TB, and SP powders also reduced the deleterious effects of AFB1 on the growth of chickens (p &lt; 0.05). In comparison with the control birds and the other treatments, broilers given AFB1-contaminated diets had a higher relative weight of abdominal fat (p &lt; 0.05). The feeding of AFB1 resulted in a substantial rise in AST and ALT activity (p &lt; 0.05). MT, TB, and SP powders significantly decreased blood AST and ALT activity in broilers (p &lt; 0.05). The AFB1 and MT groups had the lowest skin thickness (p &lt; 0.05) twenty-four hours after injection. The phytohemagglutinin injection results showed that the TB and SP were more efficient than the other additives in removing toxins from the feed sources (p &lt; 0.05). The antibody titer against sheep red blood cells (SRBCs) was lower in the AFB1 group compared to the control group at 28 days of age (p &lt; 0.05). When comparing AFB1-fed chicks to the control treatment, there was a significant (p &lt; 0.05) concentration of cecal Coliform bacteria. When MT, TB, and SP powders were added to AFB1-contaminated diet, cecal Coliforms were decreased (p &lt; 0.05). When fed AFB1-contaminated diets, it can be concluded that MT, TB, and SP are suitable for supporting growth performance, immunological function, and the serum biochemical parameters of broiler chickens.

Food supply and individual quality influence seabird energy expenditure and reproductive success.

Breeding animals trade off maximizing energy output to increase their number of offspring with conserving energy to ensure their own survival, leading to an energetic ceiling influenced by external, environmental factors or by internal, physiological factors. We examined whether internal or external factors limited energy expenditure by supplementally feeding breeding black-legged kittiwakes varying in individual quality, based on earlier work that defined late breeders as low-quality and early breeders as high-quality individuals. We tested whether energy expenditure increased when food availability decreased in both low- and high-quality birds; we predicted this would only occur in high-quality individuals capable of sustaining high levels of energy expenditure. Here, we find that food-supplemented birds expended less energy than control birds because they spent more time at the colony. However, foraging trips of food-supplemented birds were only slightly shorter than control birds, implying that food-supplemented birds were limited by food availability at sea similarly to control birds. Late breeders expended less energy, suggesting that low-quality individuals may not intake the energy necessary for sustaining high-energy output. Food-supplemented birds had more offspring than control birds, but offspring number did not influence energy expenditure, supporting the idea that the birds reached an energy ceiling. Males and lighter birds expended more energy, possibly compensating for relatively higher energy intake. Chick-rearing birds were working near their maximum, with highest levels of expenditure for early-laying (high-quality) individuals foraging at sea. Due to fluctuating marine environments, kittiwakes may be forced to change their foraging behaviors to maintain the balance between reproduction and survival.

Study of Supplementation of Various Levels of Biochar on Health and Production Performance of Growing Local Turkey (Meleagris gallopova) Poults

The study determined the hematobiochemical, lipid peroxidation and antioxidant enzyme parameters of local day-old male turkey poults (n=24), during two feeding periods, grower phase (6-15 weeks) and finisher phase (16-24 weeks). A commercial (Top® brand) chick mash served as the basal diet, while biochar supplementation levels were 5, 15 and 25g/kg at the start of the grower phase, until slaughter. Poults fed 5 and 15g/kg biochar had higher (P&lt;0.05) final body weight and average daily weight gain when compared with poults fed other treatment diets. White blood cell count was higher (P&lt;0.05) in poults fed 25g/kg biochar diet compared with those of the control group. Poults fed 5 and 15g/kg biochar diets had reduced serum (P&lt;0.05) aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, urea, creatinine, and bilirubin concentrations when compared with those of the control birds, while the lowest concentrations of uric acid were recorded in poults fed 5g/kg biochar diet. Increased (P&lt;0.05) activities of serum catalase and glutathione peroxidase were observed in 15 and 25g/kg biochar groups, coupled with decreased (P&lt;0.05) malondialdehyde values which were comparable (P&gt;0.05) with those of the control group. The results of the present study revealed that 15g/kg biochar can be incorporated in the diet of local turkey poults for improved growth performance and serum-biochemistry and reduced lipid peroxidation. However, improvement in hematology and antioxidant enzyme activity in local turkey poults require 25g/kg biochar supplementation.

Effects of early feeding of enzymatically treated yeast on growth performance, organ weights, intestinal histomorphology, and ceca microbial metabolites in broiler chickens subjected to Eimeria challenge

The study evaluated effects of early feeding of enzymatically treated yeast on growth performance and selected physiological responses in broiler chickens. A total of 480-day-old (male) Ross × Ross 708 broiler chicks were placed in 24 floor pens (20 birds per pen) and allocated to 2 diets (control vs. yeast) in a completely randomized block design (n = 12). Diets were formulated for a 5-phase feeding program: Pre-starter; d 0 to 6 Starter; d 7 to 15, Grower: d 16 to 28, Finisher 1; d 28 to 42 and Finisher 2; d 43 to 56. The yeast was applied in pre-starter and starter diets at 0.6 and 0.2%, respectively. Birds received a common diet from d 16 to 56. Feed intake (FI) and body weight (BW) were recorded by phase for calculation of BW gain (BWG) and FCR. On d 10, all birds received an oral dose of 25,000 E. acervullina and 5,000 E. maxima sporulated oocysts in 1 mL of sterile saline. On d 15 post-hatch, one bird per pen was sacrificed for organ weights (gizzard, small intestine, ceca, liver, spleen, liver, and bursa), jejunal tissues for histomorphology and ceca digesta for microbial activity. On d 56, one bird per pen was sacrificed for organs and breast weight. In pre-starter phase, yeast fed birds showed improved (P < 0.05) BWG and FCR than control fed birds. Combining pre-starter and starter phases, the FCR of yeast fed birds showed improved FCR (1.115 vs. 1.135; P < 0.05) than control. The overall BWG (d 0–56) was 3.920 and 3.962 kg/ bird and corresponding values for FCR were, 1.808 and 1.755, for the control and yeast, respectively. Diets had no (P > 0.05) effects on physiological responses evaluated on necropsied birds except that yeast birds had (P < 0.05) lighter bursa than control birds on d 15. The current data indicated that yeast could support growth in early life of broiler chickens, but these effects were not sustained after the transitioning birds to common grower and finisher diets.

Hierarchy of fear: experimentally testing ungulate reactions to lion, African wild dog and cheetah

AbstractExperiments have begun demonstrating that the fear (antipredator behavioral responses) large carnivores inspire in ungulates can shape ecosystem structure and function. Most such experiments have focused on the impacts of either just one large carnivore, or all as a whole, rather than the different impacts different large carnivores may have in intact multi-predator-prey systems. Experimentally testing the relative fearfulness ungulates demonstrate toward different large carnivores is a necessary first step in addressing these likely differing impacts. We tested the fearfulness ungulates demonstrated to playbacks of lion (Panthera leo), African wild dog (Lycaon pictus), cheetah (Acinonyx jubatus) or non-predator control (bird) vocalizations, in Greater Kruger National Park, South Africa. Ungulates ran most to lions, then wild dogs, and then cheetahs, demonstrating a very clear hierarchy of fear. Those that did not run looked toward the sound more on hearing large carnivores than controls, looking most on hearing lions. Notably, prey species-specific population level kill rates by each predator did not predict the patterns observed. Our results demonstrate that different large carnivores inspire different levels of fear in their ungulate prey, pointing to differing community-level impacts, which we discuss in relation to the ongoing worldwide decline and loss of large carnivores.

Photoperiodic control of singing behavior and reproductive physiology in male Fife fancy canaries

Temperate-zone birds display marked seasonal changes in reproductive behaviors and the underlying hormonal and neural mechanisms. These changes were extensively studied in canaries (Serinus canaria) but differ between strains. Fife fancy male canaries change their reproductive physiology in response to variations in day length but it remains unclear whether they become photorefractory (PR) when exposed to long days and what the consequences are for gonadal activity, singing behavior and the associated neural plasticity. Photosensitive (PS) male birds that had become reproductively competent (high song output, large testes) after being maintained on short days (SD, 8 L:16D) for 6 months were divided into two groups: control birds remained on SD (SD-PS group) and experimental birds were switched to long days (16 L:8D) and progressively developed photorefractoriness (LD-PR group). During the following 12 weeks, singing behavior (quantitatively analyzed for 3 × 2 hours every week) and gonadal size (repeatedly measured by CT X-ray scans) remained similar in both groups but there was an increase in plasma testosterone and trill numbers in the LD-PR group. Day length was then decreased back to 8 L:16D for LD-PR birds, which immediately induced a cessation of song, a decrease in plasma testosterone concentration, in the volume of song control nuclei (HVC, RA and Area X), in HVC neurogenesis and in aromatase expression in the medial preoptic area. These data demonstrate that Fife fancy canaries readily respond to changes in photoperiod and display a pattern of photorefractoriness following exposure to long days that is associated with marked changes in brain and behavior.

Co-administration of recombinant chicken IL-7 or chicken NK-lysin peptide 2 increases efficacy of Eimeria tenella elongation factor-1α in Eimeria maxima infected chicken

Abstract This study was conducted to improve the efficacy of recombinant Eimeria tenella elongation factor-1α (EF-1α) antigen by co-administrating recombinant chicken IL-7 or chicken NK-lysin peptide 2 in Eimeria maxima-challenged chickens. On day 4, birds were administered with following five groups: (CON) control birds without Eimeria infection, (NC) sterile PBS solution plus adjuvant (ISA 78 VG), (COM 1) 100 μg of recombinant EF-1α plus ISA 78 VG, (COM 2) COM 1 component plus 1 μg of recombinant chIL-7, and (COM 3) COM 2 component plus 5 μg of cNK2 peptide. One week after, the boosting immunization were administrated with same concentration of components as the primary immunization. All birds except CON were orally inoculated with E. maxima (1.0 × 104 oocysts/bird) on day 19. Animal experiment demonstrated that the birds immunized with recombinant EF-1α showed greater serum anti EF-1α level, and co-administration of recombinant chIL-7 increased the level of IL-7 in serum. Vaccination of COM 2 mitigated intestinal lesion formation at 6 days post-infection (dpi) and increased body weight at 6 dpi and 9 dpi. Vaccination of COM 3 reduced fecal oocyst shedding compared with NC. E. maxima infection up-regulated expression level of jejunal proinflammatory cytokines (IL-β, IL-17F) and type I cytokines (IFN-γ and IL-10), and those expression levels were decreased by administration of COM 1, COM 2 or COM 3. Down-regulated expression of tight junction (TJ) protein (Jam2 and Occludin) by E. maxima challenge were increased by COM 2or COM 3, respectively. Overall animal experiment results demonstrated a potential effect that co-administration of recombinant IL-7 or cNK-2 peptide can increase the efficacy of recombinant EF-1α in E. maxima-infected chicken. Funding was partly supported by ARS CRIS 8042-32000-107-00D, NIFA SBIR 2015-33610-23499, and NIFA SBIR 2016-33610-25686.

GSK-3β Inhibition in Birds Affects Social Behavior and Increases Motor Activity.

Glycogen synthase kinase-3 (GSK-3) is a highly conserved serine/threonine protein kinase that plays a central role in a wide variety of cellular processes, cognition and behaviour. In a previous study we showed that its α and β isozymes are highly conserved in vertebrates, however the α gene is missing in birds. This selective loss offers a unique opportunity to study the role of GSK-3β independently. Accordingly, in the present study we aimed to investigate the role of GSK-3β in social behaviour, motivation, and motor activity in zebra finches (Taeniopygia guttata). We did that by selective inhibition of GSK-3β and by using tests that were specifically designed in our laboratory. Our results show that GSK-3β inhibition: 1) Affected social recognition, because the treated birds tended to move closer towards a stranger, unlike the control birds that stood closer to a familiar bird. 2) Caused the treated birds to spend more time in the more middle parts of the cage compared to controls, a behaviour that might indicate anxiety. 3) As the experiment progressed, the treated birds took less time to make a decision where to stand in the cage compared to controls, suggesting an effect on decision-making. 4) Increased in the motor activity of the treated birds compared to the controls, which can be regarded as hyperactivity. 5) Caused the treated birds to pass through a barrier in order to join their flock members faster compared to controls, and regardless of the increase in the level of difficulty, possibly suggesting increased motivation. Our study calls for further investigation, because GSK-3 is well acknowledged as a central player in regulating mood behaviour, cognitive functions, and neuronal viability. Therefore, studying its impact on normal behaviour as we did in the current study, unlike most studies that were done in diseases models, can advance our understanding regarding GSK-3 various roles and can contribute to the discovery and development of effective treatments to repair cognition and behaviour.

Inflection in nutrient transporter genes leads to potential changes in small intestine histomorphology with improved nutrient retention in chicken under dietary synbiotic supplementation

This study investigated the role of synbiotic supplementation on gut histomorphology, expression of nutrient transporters, and nutrient utilization in broiler chicken. Bacitracin methylene disalicylate (BMD), Probiotic Lactobacillus acidophilus (LBA), and prebiotic Mannan-oligosaccharides (MOS) were used to formulate total 6 dietary treatments viz. T1 (control; basal diet), T2 (BMD @ 20 mg/kg diet), T3/T4 (0.1% MOS with 106 and 107 cfu LBA/g diet), and T5/T6 (0.2% MOS with 106 and 107 cfu LBA/g diet). A total of 288 day old chicken were allocated at random among six treatments, each with six replicates of eight chicken (48 birds/treatment). Results revealed higher villus height, crypt depth, villus height: crypt depth ratio, and histological surface magnification ratio values in chicken fed a combination of MOS (0.2%) and LBA (106 or 107 cfu/g diet). BMD supplemented birds had higher values of these parameters compared to control birds. The villus width, villus bottom area, and mucosal unit bottom area were all increased in birds supplemented with BMD, but were similar to birds fed a combination of MOS (0.1 percent) and LBA (107 cfu/g diet). The villus width, villus bottom area, and mucosal unit bottom area were higher in BMD supplemented birds which were similar to the birds fed a combination of MOS (0.1%) and LBA (107 cfu/g diet). The birds fed a combination of MOS (0.2%) and LBA (106 or 107 cfu/g diet) revealed upregulation of SGLT1 and GLUT5 expression in jejunum but no significant effect was observed on the expression of PePT1 and EAAT3 gene. The AME Diet, nitrogen, phosphorus, and calcium retentions were higher in birds fed a combination of MOS (0.2%) and LBA (106 or 107 cfu/g diet). However, the organic matter digestibility was higher in birds fed a combination of MOS (0.2%) and LBA (106 cfu/g diet) and BMD supplementation also improved the organic matter utilization compared to control. In conclusion, the supplementation of a combination of MOS (0.2%) and LBA (106 or 107 cfu/g diet) improves the intestinal architecture along with upregulation of SGLT1 and GLUT5 nutrient transporters and increase in nutrient digestibility in broiler chicken.