The effect of feed-based vaccination on tilapia farm endemic for streptococcosis

Abstract

A tilapia farm experiencing endemic streptococcosis was selected to study the effect of vaccination with a feed-based vaccine on naturally ocurring streptococcosis. A total of 9000 red tilapia, Oreochromis niloticus × Oreochromis mossambicus of 100 ± 20 g were divided into 9 cages. Fish of Group 1 in cages 1, 2 and 3 were not vaccinated. Group 2 in cages 4, 5 and 6 were vaccinated on days 0 and 14 (single booster) while Group 3 in cages 7, 8 and 9 were vaccinated on days 0, 14 and 42 (double booster). Vaccination was done by oral administration of the feed-based bacterin vaccine at 4% bodyweight. Samples of serum for antibody study and the brain, eyes and kidney for bacterial isolation were collected at 14-day intervals. The study was carried out during the critical months between April and June. Following vaccination and booster, there was significant (p < 0.05) increase in the antibody levels in all vaccinated groups from week 1 that reached the peak at week 3 before declining gradually until week 6. However, second booster on week 6 significantly (p < 0.05) increased the antibody level that remained high until the end of the 16-week study period (double booster). Streptococcus agalactiae was isolated at the start of the experiment (day 0) at an average of 10 ± 5.0% of the sampled fish. In week 4, the isolation rate was 13 ± 5.7% but increased to 18 ± 7.6% in week 8, to 25 ± 10.0% in week 10, to 28 ± 5.8% in week 12 and 25 ± 7.3% in week 14. The average isolation rate was 28 ± 7.2%, 18 ± 7.1% and 13 ± 8.2% of the fish sampled from unvaccinated, single booster and double booster groups, respectively. At the end of the study period, the survival rate was 45.2 ± 2.45% for unvaccinated, 65.3 ± 4.8% for single booster and 75.1 ± 2.1% for double booster groups. Vaccinating fish in endemic farm might not eliminate the disease but was able to significantly improve the survival rate.

Vaccination of Tilapia against Motile Aeromonas Septicemia: A Review

“…Ismail et al. (, ) also showed that antibody titers and host survival (75.1%) of a double booster vaccination were significantly higher than those of a single vaccination against S. agalactiae in tilapia. Thus, antigen dose should be optimized to correspond with vaccine protection in immunized fish (Dubey et al.…”

“…Despite the fact that the tilapia industry has improved rapidly, it also faces huge challenges from different catastrophic bacterial and viral diseases (Ismail et al. , ). Among these infectious bacterial diseases, the most common are motile aeromonad septicemia (MAS) (Cruz‐Papa et al.…”

Involvement of cholinergic and adenosinergic systems on the branchial immune response of experimentally infected silver catfish with Streptococcus agalactiae

“…This disease is characterized by loss of appetite, exophthalmia, eye haemorrhage, corneal opacity, distended abdomen, curvature of the spinal cord, abnormal swimming behaviour and severe inflammation (Asencios et al., ; Iregui, Comas, Vásquez, & Verján, ; Van Doan et al., ), causing high mortality and severe economic losses in species such as red tilapia ( Oreochromis sp.) (Isiaku et al., ), Nile tilapia ( Oreochromis niloticus ) (Van Doan et al., ) and Mozambique tilapia ( Oreochromis mossambicus ) (Ismail et al., ). In the particular interest, the gills are considered one of the most affected tissues by S. agalactiae, causing severe histological alterations characterized by congestion, haemorrhage and proliferation on inflammatory cells, that contributes to high mortality (Su et al., ).…”

Differential PCR detection of Streptococcus agalactiae and Streptococcus iniae in tilapia (Oreochromis niloticus) by a single primer pair

“…With the development of selective and intensive culture, tilapias have been reported to be severely infected by pathogenic Streptococcus, and the resultant streptococcosis is one of the key fish diseases with high morbidity and mortality rates (Amal & Zamrisaad, ; Shen, Ma, Liu, & Yue, ). It has been estimated globally that the economic losses caused by streptococcosis outbreaks were as high as ten billion dollars annually (Ismail et al, ). S. agalactiae and S. iniae were recently discovered as the two most frequently detected pathogenic bacteria that trigger streptococcosis with similar clinical signs in the infected tilapia.…”

“…Streptococcosis reported in intensive aquaculture systems is a major disease of tilapia which is usually caused by S. agalactiae and S. iniae infections and results in high economic loss in the aquaculture industry (Amal & Zamrisaad, ; Ismail et al, ; Najiah, Wei, & Nadirah, ). S. agalactiae and S. iniae have been reported to be present in the same geographic area and even on the same farm; therefore, in many cases, proper detection techniques are required to diagnose S. agalactiae and S. iniae simultaneously.…”