A Novel Nanobody-Horseradish Peroxidase Fusion Based-Competitive ELISA to Rapidly Detect Avian Corona-Virus-Infectious Bronchitis Virus Antibody in Chicken Serum

A review on camelid nanobodies with potential application in veterinary medicine

The single variable domains of camelid heavy-chain only antibodies, known as nanobodies, have taken a long journey since their discovery in 1989 until the first nanobody-based drug's entrance to the market in 2022. On account of their unique properties, nanobodies have been successfully used for diagnosis and therapy against various diseases or conditions. Although research on the application of recombinant antibodies has focused on human medicine, the development of nanobodies has paved the way for incorporating recombinant antibody production in favour of veterinary medicine. Currently, despite many efforts in developing these biomolecules with diversified applications, significant opportunities exist for exploiting these highly versatile and cost-effective antibodies in veterinary medicine. The present study attempts to identify existing gaps and shed light on paths for future research by presenting an updated review on camelid nanobodies with potential applications in veterinary medicine.

Response of broiler breeder pullets when fed hydrolyzed whole yeast from placement to 22 wk of age

The study examined the effects of feeding broiler breeder pullets hydrolyzed whole yeast (HY) from hatch to 22 wk of age (WOA). A total of 524-day-old Ross 708 pullets were placed in floor pens (∼24 birds/pen) for the starter (0-4 WOA) and grower (5-18 WOA) phases, then transferred to the egg production facility and redistributed to ∼20 birds/pen for the prelay phase (19-22 WOA). Two diets were allocated to pens (0-18 WOA; n = 11) and (19-22 WOA; n-12). The diets were a control corn and soybean meal diet formulated to meet specifications and control plus 0.05% HY (HY). Birds had ad libitum access to feed in the first week and daily feed allocation based on pen BW from 2 WOA. Birds had free access to water throughout the trial. Body weight (BW) and uniformity (BW CV) were monitored. Boosters for infectious bronchitis and New Castle disease vaccines were administered at 18 WOA, and samples of pullets bled for antibody titer 5-day later. One pullet/pen was randomly selected, weighed, bled for plasma biochemistry, and necropsied for organ weights, ceca digesta for short-chain fatty acids (SCFA), and leg bones morphometry. In the starter and grower phases, birds fed HY were lighter and gained less (P < 0.05) than control birds. However, there were no diet effects (P > 0.05) on growth, the BW prelay phase, or BW uniformity throughout the trial. There were no (P > 0.05) diet effects on breast, gastrointestinal, liver and bursa weights, serum antibody titers, plasma biochemistry, SCFA and bone attributes. However, pullets fed HY had heavier (P = 0.047) spleen and tended to have lower (P = 0.080) plasma concentrations of aspartate aminotransferase (AST) relative to control pullets. In conclusion, the parameters assessed showed no negative consequences of feeding HY to broiler breeder pullets. However, effects on the spleen and plasma AST may indicate modest modulation of immunity and metabolism. The impact of the provision of HY during broiler breeder pullet phase on reproductive performance and chick quality should be investigated.

Development of a Recombinant Enzyme-Linked Immunosorbent Assay for the Detection of Antibodies Against Infectious Bronchitis Virus

Infectious bronchitis virus (IBV), a gammacoronavirus within the Coronaviridae family, is an economically important etiological disease agent in chickens. Both early diagnosis and determination of the immune status of chickens are important for controlling IBV outbreaks in chicken flocks. The N protein is the most abundantly expressed virus-derived protein during IBV infection and can induce a strong immune response by producing antibodies during early infection or immunization. In this study, we found that the amino acid sequences of the N protein between CK/CH/LJL/04I and the other 22 IBVs were conserved, especially in the 1-160 amino acid region. Based on the sequence similarities, the three recombinant proteins, rN160 (amino acid positions 1-160), rN266 (144-409), and rN409 (1-409), were expressed using the Escherichia coli system and subsequently purified. The results demonstrated that the antigenicity and reactivity of rN160 were better than those of rN266 and rN409. As a result, an indirect enzyme-linked immunosorbent assay (ELISA) (rN160 ELISA) was developed to detect the IBV antibody based on the rN160 protein. Using 1,500 clinical field serum samples, the relative sensitivity, specificity, and accuracy of the rN160 ELISA were 98.97%, 92.34%, and 97.93%, respectively, compared to those of a commercial ELISA kit (IDEXX), indicating a strong positive correlation between the two methods. Taken together, these results reveal that the rN160 ELISA is a rapid, simple, and sensitive method for detecting group-specific IBV antibodies for epidemiological investigation and antibody-level monitoring.