Introduction: Avian pathogenic Escherichia coli (APEC) is a leading cause of extraintestinal infection and heavy economic losses. Imparting immunity after vaccination with live attenuated strain vaccination is an ideal strategy for infection control. This study considers an FtsK knockout mutant strain as a candidate. Material and Methods: An FtsK knockout mutant of APEC strain E058 was constructed and the pathogenicity of the mutant and wild-type strains was further evaluated in chickens. Results: The 50% lethal doses of each strain for one-day-old specific-pathogen-free (SPF) chickens challenged experimentally via trachea were 10⁵.⁵ and 10⁷.⁰ colony-forming units (CFU) respectively. Chickens challenged with the wild-type strain exhibited typical signs and lesions of avian colibacillosis, while those inoculated with the mutant strain showed mild pericarditis and pulmonary congestion. The growth rate of the FtsK mutant strain was much slower than the wild-type strain in the heart, spleen, liver, and lung of infected chickens. Conclusion: These results indicated that the APEC FtsK mutant can be attenuated for chickens, and that this mutant has the potential for the development of an APEC vaccine.

Objective: This study was conducted to compare between the nanoparticles of copper (Cu-NP) and copper sulfate (CuSO4) effect on immunity, pro-inflammatory cytokine, oxidant/antioxidant balance, different behavioral patterns, growth rate, and weight gain by adding them in drinking water of broilers. Materials and Methods: One hundred and fifty broiler chicks of 1-day-old were randomly divided into three groups: the first group was the control, the second group received CuSO4 in drinking water (10 mg/l), and the third group received Cu-NP in drinking water (10 mg/l) with replicates (n = 25) for 5 weeks of age. Blood samples collected for estimating immunoglobulins (A, G, and M), superoxide dismutase, pro-inflammatory (IL-6), erythrocyte sedimentation rate, heterophil/ lymphocyte (H/L) ratio, malondialdehyde (MDA), corticosterone hormone, and lymphoid organs index weight. Moreover, behavioral observations were undertaken from the 2nd week until the 5th week of age for measuring different behavioral patterns (feeding, drinking, crouching, body care, and comfort behaviors). Chicks were individually weighed weekly (gm); also, the weight gain, the intake of food, and the ratio of feed conversion were calculated. Results: Cu-NP administration has improved the blood profile, lymphoid organs index weight in Cu-NP treated broilers in relation to control and CuSO4 treated groups. Conversely, erythrocyte sedimentation rate, H/L ratio, MDA, and corticosterone hormone were reduced by Cu-NP treat¬ment. Moreover, Cu-NP has a positive effect on all behavioral patterns more than other groups which significantly reflect on the weight of the body, gaining of weight, and the intake of food in the Cu-NP treated group of birds. Conclusion: The findings in this study stated that when the drinking water of broilers was supple¬mented with Cu-NP, there might be an improvement in the immunity, behavior, and productive performance more efficiently than CuSO4. [J Adv Vet Anim Res 2020; 7(1.000): 16-25]

The primary objective of this observational study was to examine the association between passive transfer of immunity and growth performance in preweaning calves. A secondary objective was to evaluate the utility of a heart girth tape (HGT) to estimate body weight (BW) in preweaning calves. A total of 142 Holstein calves were enrolled in this study. Blood samples were collected 24 to 48 hours after birth and serum immunoglobulin G (IgG) concentration for each calf was measured by radial immunodiffusion assay. Calf BW was determined at birth, at 21 days, and at weaning using an electronic scale (ES) and HGT. A significant positive association was detected between serum IgG and both BW at 21 days and average daily gain (ADG) from 0 to 21 days of life. Additionally, ADG from 0 to 42 days of life showed a trend toward an improved rate of gain as IgG concentration increased. The Pearson correlation coefficient between BW obtained from ES and HGT was 0.81 at birth, 0.86 at 21 days, and 0.83 at weaning. The mean differences between BW obtained from ES and HGT were -3.1 kg at birth, -3.2 kg at 21 days, and -7.7 kg at weaning. In conclusion, serum IgG concentration in neonatal calves is an important contributing factor for the variation in growth performance of preweaning calves. The HGT can be used to estimate the BW of preweaning calves but has a tendency to overestimate weight, especially at weaning compared to birth and 21 days of age.

This study was planned to evaluate the extracts of Aloe vera (AV) at three different pH as a growth promoter, immunostimulant and coccidiostat agent in broiler production. This experiment was undertaken for a period of 35 days in the Institute of Animal Sciences, Faculty of Animal Husbandry, University of Agriculture Faisalabad, Pakistan. A total of 150 dayold broiler birds (Cobb) were randomly assigned to 5 treatments with 3 replicates of 10 chicks each. Birds were offered commercial broiler starter and finisher diets supplemented with 100 mg/kg enramycin (ANT), 50 ml/liter AV of pH 3 (AV1), 50 ml/liter AV of pH 7 (AV2), 50 ml/liter AV of pH 12 (AV3) and only fresh clean water (CON).

Objective—To evaluate the long-term protective immunity of a cyprinid herpesvirus 3 (CyHV3) vaccine in naïve koi (Cyprinus carpio koi). Animals—72 koi. Procedures—Vaccinated koi (n = 36) and unvaccinated control koi (36) were challenge exposed to a wild-type CyHV3 strain (KHVp8 F98-50) 13 months after vaccination. Results—The CyHV3 vaccine provided substantial protective immunity against challenge exposure. The proportional mortality rate was less in vaccinated koi (13/36 [36%]) than in unvaccinated koi (36/36 [100%]). For koi that died during the experiment, mean survival time was significantly greater in vaccinated than in unvaccinated fish (17 vs 10 days). Conclusions and Clinical Relevance—The CyHV3 vaccine provided substantial protective immunity against challenge exposure with CyHV3 13 months after vaccination. This provided evidence that koi can be vaccinated annually with the CyHV3 vaccine to significantly reduce mortality and morbidity rates associated with CyHV3 infection.

The innate immune system is a critical component directing the overall response of the immune system early in the inflammatory process. Evaluation of the innate immune system could offer a screening method for the selection of breeding stock from commercial chicken operations to improve flock health and prevent the loss of genes crucial to disease resistance. Three commercial broiler chicken lines (designated Lines A, B and C) were profiled for efficiency of their innate immunologic response. Oxidative burst and bactericidal functions of heterophils and monocytes, as well as heterophil degranulation, were analyzed. The birds were tested 1, 4, 8 and 15 days post-hatch. Individual lines differed in their ability to perform innate immunological responses during the first 15 days post-hatch. Although bactericidal capabilities were similar, oxidative burst responses by monocytes were low in comparison to that generated by heterophils. The fact that monocytes are not particularly adept at producing an oxidative burst at this age suggests that this is not a major avenue of innate defense by monocytes. Heterophil oxidative burst response was stronger in Line C than Line A during the first four days post-hatch. Line B showed no difference from Line C in heterophil oxidative burst response at 1 d, but produced a stronger response than Line C on 4 and 8 d post-hatch. Degranulation by heterophils showed significant differences in responses of Lines A and C depending on the day post-hatch, and stronger response in Line C vs Line B in the first four days post hatch. The first week post-hatch is an important time as chicks are particularly susceptible to infection as neonates. Mortality data of the commercial lines indicates that Line A is the most susceptible to demise, followed by Line C and then Line B. These results suggest that oxidative burst production efficiency is an important defensive function to monitor for immunoprofiling.

Colostrum-deprived calves (n = 34) were fed various amounts of colostrum, colostrum substitute, or milk replacer to establish a range in titer of passively acquired viral neutralizing antibody in serum. The calves were then challenge exposed intranasally with a virulent, noncytopathic bovine viral diarrhea virus (BVDV-890). After viral challenge exposure, calves were monitored for fever, leukopenia, thrombocytopenia, and diarrhea. In addition, viral isolation and viral titration were performed on specimens of nasal secretions, buffy coat cells, and serum obtained from the calves. Fever and systemic spread of virus were detected in calves that had viral neutralizing titer of 256 or lower. Calves that had viral neutralizing titer lower than 16 developed severe clinical disease manifested by fever, leukopenia, thrombocytopenia, and diarrhea. Seventy and duration of signs of disease decreased as titers of passively acquired viral neutralizing antibody increased. These results indicate that low to intermediate titers of passively acquired viral neutralizing antibody were not sufficient to fully protect calves from virulent bovine viral diarrhea virus.

Passive protection provided by sows inoculated with the virulent Miller strain of transmissible gastroenteritis virus (TGEV), or the ISU-1 strain of porcine respiratory coronavirus (PRCV), or both was evaluated in nursing pigs challenge exposed with virulent TGEV. Four sows (group B) were inoculated with PRCV oronasally twice at 4 and 2 weeks before parturition; 1 sow (group C) was inoculated similarly, but in 2 subsequent pregnancies; and 2 sows (group D) were oronasally primed with PRCV at 4 weeks before parturition, and 2 weeks later were administered a booster inoculation of virulent TGEV. Two additional sows (group E) remained uninoculated and served as seronegative controls, and 1 sow (group A) that had been naturally infected with TGEV served as a seropositive control. The degree of passive immunity transferred by these sows to their litters was assessed by challenge exposing the pigs of sows in groups BE (only the second litter of group C) with virulent TGEV at 3 to 5 days of age. After challenge exposure, clinical signs of infection and mortality were noted and fecal and nasal shedding of virus was assessed by ELISA. The IgA, IgG, and IgM antibody titers to TGEV were quantified in colostrum and milk of the sows by use of an isotype-specific monoclonal antibody-capture ELISA, using biotinylated monoclonal antibodies against each porcine isotype as detecting reagents. A plaque-reduction assay was used to quantify neutralizing antibody titers in serum, colostrum, milk, and fractionated whey (IgG and IgA/IgM). In the sow naturally infected with TGEV (group A), there was a pronounced decrease in IgG antibody titers to TGEV in the transition from colostrum to milk, and IgA TGEV antibodies became predominant, with high titers maintained throughout lactation. The 4 group-B sows partially protected their pigs after TGEV challenge exposure; mean mortality was 67%, compared with 100% in pigs suckling the 2 TGEV seronegative control sows (group-E litters). Although IgA TGEV antibodies were detected in colostrum and milk of group-B sows, IgG TGEV antibodies were the most abundant. The sow of group C had a marked increase in IgA TGEV antibody titers in colostrum and milk after reinoculation with PRCV during the second pregnancy, before TGEV challenge exposure of the litter. Its pigs were passively protected to a high degree after TGEV challenge exposure (27% litter mortality). The sows in group D, primed with PRCV and boosted with TGEV, provided the best passive protection after TGEV challenge exposure of their pigs. Not only litter mortality (27%) but also morbidity was reduced, compared with those factors for the other challenge exposed litters, and the sows did not become ill. In these swine, the high degree of passive protection observed could not be associated with the presence of only IgA TGEV antibodies in the milk, but high IgM TGEV antibody titers also were detected in colostrum and milk. Results of this study suggest that PRCV-inoculated sows are able to partially protect their pigs from TGEV challenge exposure and, on the basis of preliminary data, the degree of protection may increase after multiple PRCV exposures or after secondary exposure to TGEV during pregnancy. Also, an IgA respiratory tract-mammary gland link may exist as evident by the low titer of IgA TGEV antibodies in the milk of PRCV-inoculated sows, but may not be as efficient in inducing lactogenic IgA immunity as is the gastrointestinal tract-mammary gland link.

An avirulent live Salmonella choleraesuis culture (SC-54) was evaluated for use as an effective vaccine in preventing salmonellosis caused by S choleraesuis in pigs. Eighty-two pigs, 3 to 4 weeks old, were randomly assigned to 1 of 2 treatment groups, which were designated as either vaccinates or controls. After vaccination, all pigs were examined for fecal shedding of S choleraesuis, rectal temperature, and 10 clinical variables. Significant difference was not detected between vaccinated and nonvaccinated pigs for 14 days (phase I) after intranasal administration of the vaccine. Efficacy and duration of immunity were examined by intranasally challenge exposing respective pigs from either treatment group with a virulent field isolate of S choleraesuis at 2, 8, or 20 weeks after vaccination (phases II-IV). Pigs were again evaluated for 14 days after challenge exposure, and 10 clinical variables and rectal temperature were monitored. Surviving pigs were euthanatized and evaluated for gross lesions, and samples of 7 organs were collected. These organ samples were homogenized, and level of S choleraesuis infection was determined. After virulent challenge exposure during phases II-IV, the clinical status of the SC-54 vaccinates was significantly (P < 0.05) superior to that of nonvaccinates for rectal temperature, feces consistency, behavior, appetite, body condition, and mean score for the 10 clinical variables. Quantitative bacteriologic culture of the tonsil, lung, liver, spleen, mesenteric lymph nodes, ileum, and colon samples indicated consistent reduction of organ colonization in vaccinates; bacteria numbers in the mesenteric lymph nodes, lungs, and ileum were significantly (P < 0.05) reduced. Gross lesions in pigs indicated reduction of pneumonia in vaccinates. Pigs also had consistent weight gain throughout all phases of the study after challenge exposure, although the differences were not significant. In conclusion, a single intranasally administered dose of SC-54 given to 3- to 4-week-old pigs proved to be safe and efficacious and to provide protection to pigs at least 20 weeks after initial vaccination.

Persistence of the vaccine RH strain of Toxoplasma gondii was studied by bioassay and histologically in 14 pigs. Pigs were euthanatized 2, 4, 7, 8, 14, 15, 21, 29, 36, 42, 52, 57, and 76 days after IM inoculation with 100,000 T gondii tachyzoites. Viable T gondii tachyzoites derived from the RH strain were isolated by bioassay in mice inoculated with tissues of pigs euthanatized up to 14 days after vaccination. Except for fever, pigs vaccinated IM with the RH strain remained clinically normal. Two other pigs inoculated IV with 100,000 T gondii tachyzoites of the RH strain became ill, and 1 pig was comatose by 4 days after inoculation. These findings indicate that route of inoculation may influence the response of pigs to T gondii. To evaluate protective immunity in pigs vaccinated with the RH strain, 16 age-matched pigs were allotted to 4 groups (A-D) of 4 pigs each. Eight pigs (groups A and C) were vaccinated IM with 100,000 RH strain tachyzoites and 8 pigs (groups B and D) were nonvaccinated controls. Pigs of groups A and C were challenge-inoculated orally with a lethal dose of T gondii oocysts (100,000 oocysts) 81 days after vaccination, pigs of groups B and D were inoculated similarly 220 days after vaccination. The concentration of T gondii at 3 days after challenge inoculation of pigs vaccinated 81 days earlier was reduced 100,000-fold in mesenteric lymph nodes, compared with that in a nonvaccinated pig euthanatized at 3 days after challenge inoculation. Another nonvaccinated pig became comatose and had to be euthanatized at 7 days after challenge inoculation, numerous tachyzoites were in its mesenteric lymph nodes, intestines, and liver. The vaccinated pigs generally remained clinically after challenge inoculation with oocysts. Toxoplasma gondii was not isolated by bioassays from tissues of 5 of 8 vaccinated pigs, but was recovered from all nonvaccinated pigs. Results indicate that protective immunity persisted in pigs for at least 7 months after vaccination with the nonpersistent RH strain of T gondii.