Poultry Science

Aim: Newcastle disease (ND) is an important viral disease for poultry caused by avian paramyxovirus which can be identified by its nature of agglutination activity with red blood cell (RBC) of different species. The study was aimed to characterize the hemagglutinating (HA) activity of ND virus (NDV) at three different temperatures using RBC of five avian species, six mammalian species, and eight different human blood groups. Materials and Methods: The study was conducted from January to December 2014 at Chittagong Veterinary and Animal Sciences University. Five avian and six different mammalian species were selected for the study. In each species, two blood samples were collected aseptically. Eight different blood groups (A+, A−, B+, B−, AB+, AB−, O+, and O−) were studied in human. HA test was performed using two virus strains ND lasota and field isolate of very virulent NDV (VVNDV) with mentioned species of RBC at chilling (4°C), incubating (37°C), and room temperature (24°C). Results: Avian RBC requires less time for agglutination than mammalian RBC. Incubation temperature (37°C) requires lowest time and chilling temperature requires highest time for agglutination of RBC. Duck RBC requires lowest time (17.81 min) while chicken RBC needs highest (57.5 min) time for HA at incubation temperature and at chilling temperature, respectively, against ND lasota virus and with field strain. Goat RBC requires significantly higher time for HA (184.68 min) at chilling temperature than other mammalian species. Human RBC requires almost similar time but O+ and O− blood group do not show any HA activity. Significant variation (p<0.05) found in quail RBC at incubation temperature. In mammalian species, a significant difference (p<0.05) has been observed in goat and horse RBC at chilling; horse and dog RBC at incubation; goat, horse, buffalo, and dog RBC at room temperature. In human, significant variation (p<0.05) has been found in A+, A− and B− blood group in chilling, in B+ blood group at incubation and A+, B+, B−, AB− blood group at room temperature against two virus strains. Conclusion: ND is considered as an economically significant disease which is highly contagious in nature infecting many avian species. The threat of ND outbreak to poultry industry necessitates effective control measures to reduce the burden in commercial and backyard farming in Bangladesh.

Background and Aim: In recent decades, the use of various feed supplements is the current trend in poultry farming, among which phytogenics serve as alternatives to feed antibiotics. This study aimed to examine the effect of feeding various doses of milk thistle extract (Silybum marianum) on the morphological and biochemical parameters of the blood in broiler chickens.

Materials and Methods: Experiments were carried out in an industrial poultry farm on broiler chickens of the Hubbard ISA F15 cross for 40 days. One control group and five experimental groups of day-old chickens were formed. The number of birds in each group was 50. Broilers of all groups received complete feed, and the experimental groups received an additional milk thistle extract at doses of 0.1, 0.5, 1.0, 1.5, and 2.0 mg/kg of body weight. Milk thistle medicinal plant extract was obtained using water-ethanol extraction followed by low-temperature vacuum drying. For the assessment of blood analyses, samples were collected from the wing vein of six chickens per group. Using unified methods recommended by the International Federation of Clinical Chemistry, the content of red blood cells, hemoglobin, white blood cells, total protein, protein fractions, triglycerides, glucose, calcium, phosphorus, and the concentration of alanine aminotransferase and aspartate aminotransferase in the blood serum were determined.

Results: It was found that the introduction of milk thistle extract into the diet of broiler chickens with the aforementioned doses increased the number of red blood cells, hemoglobin, white blood cells in the blood, as well as a decrease in the level of albumin and an increase in the content of γ-globulins in its serum.

Conclusion: The authors assume that the introduction of milk thistle extract into a complete feed for broiler chickens increased the anabolic processes in their bodies, accompanied by increased use of proteins of the albumin fraction as the main material for organogenesis.

Background and Aim: Roundworms cause infections in the avian population that lead to illness and poor production. The singing zebra dove is an economically important animal in the Indo-Malay region. The prevalence of these parasitic groups in zebra doves is unknown. This study estimated the prevalence and associated human risk factors of gastrointestinal nematode infections in zebra dove farming.

Materials and Methods: A cross-sectional survey was conducted from January to April 2021. The study was conducted on 184 doves in three zebra dove farms. Fecal samples were collected from pooled zebra dove droppings. Major proportions and infection intensity of gastrointestinal nematodes were morphologically identified and morphometrically investigated. Associated human factors were assessed through the interview surveys among farmers.

Results: Results showed that 36.96% of the zebra doves were infected. The primary nematodes were Ascaridia galli (34.78%), Heterakis gallinarum (6.52%), Trichostrongylus tenuis (2.17%), Syngamus spp. (4.35%), and Amidostomum spp. (2.17%). The primary human factors that contribute to parasitic infection were poor hygiene, food contamination with parasites, and inappropriate deworming.

Conclusion: There was a high prevalence of gastrointestinal nematodes in the zebra dove in the close cage system. Human factors played key roles as risk factors, and improves farming management will help reduce parasitic infections. However, these nematodes may contribute to poor health status and poor productivity of zebra doves. Further extensive studies on clinical signs and pathological changes should be conducted.

Antibiotics have long been recognized as growth promoters and disease controllers in poultry production. However, due to rising public health concerns over antibiotic-resistant bacteria, the use of antibiotics in livestock and poultry feed has been banned in the European Union since 2006. Thus, this study was conducted to determine the effects of oregano powder (OP) as phytobiotic feed additives on the growth performance and cell-mediated immunity of broiler chickens. A total of sixty-day-old Cobb-broiler chickens were used in the study and arranged in a Completely Randomized Design experimental set-up with four dietary treatments. Each treatment was replicated three times, having five birds in every replication. The experimental rations containing graded levels of OP (0%, 1%, 3%, and 5%) were formulated and fed ad libitum in 42 days feeding trial. The results indicated that broiler chickens fed with OP showed a significant increase (p<0.05) in the final weight, body weight gain, voluntary feed intake, and feed conversion ratio. The cell-mediated immunity showed no significant difference (p>0.05) among treatment means. However, the results revealed that the immune organ indicators of broiler chickens fed with OP were higher than those birds without OP in the diet. On the other hand, the total expenses of broiler chickens fed with 5% oregano powder were reduced by 5.81% of the total inputs, and the income generated increases as high as 30.86% of the return above feed and chick cost. In conclusion, 5% oregano powder can be incorporated without adverse effects on the production performance and cell-mediated immunity.

Background and Aim: The Marek's disease virus (MDV) is a neoplastic disease causing serious economic losses in poultry production. This study aimed to investigate MDV occurrence in poultry flocks in the Lower Egypt during the 2020 breakout and genetically characterized Meq, gL, and ICP4 genes in field strains of MDV.

Materials and Methods: Forty samples were collected from different breeds from eight Egyptian governorates in 2020. All flocks had received a bivalent vaccine (herpesvirus of turkey FC-126 + Rispens CVI988). However, weight loss, emaciation, reduced egg production, paralysis, and rough/raised feather follicles occurred. Samples were collected from feather follicles, liver, spleen, and nerve tissue for diagnosis by polymerase chain reaction. MDV genetic characterization was then performed by sequencing the Meq, gL, and ICP4 genes of five positive samples representing different governorates and breeds.

Results: A total of 28 samples were positive for MDV field strains, while two were related to MDV vaccinal strains. All samples tested negative for ALV (A, B, C, D, and J) and REV. Phylogenetic analysis of the Meq gene of sequenced samples revealed that all MDVs were related to the highly virulent European viruses (Gallid herpesvirus 2 ATE and PC12/30) with high amino acid (A.A.) identity 99.2-100%. Alternatively, there was low A.A. identity with the vaccine strains CVI988 and 3004 (up to 82.5%). These results indicate that further investigation of the efficacy of current Egyptian vaccines is required. The Egyptian strains also harbor a specific mutation, allowing clustering into two subgroups (A and B). By mutation analysis of the Meq gene, the Egyptian viruses in our study had R101K, P217A, and E263D mutations present in all Egyptian viruses. Furthermore, R176A and T180A mutations specific to our strains contributed to the high virulence of highly virulent strains. There were no mutations of the gL or ICP4 genes.

Conclusion: Further studies should evaluate the protection contributed by current vaccines used in Egypt.