Transcription profile of target genes in the Pacific White Shrimp (Litopenaeus vannamei) kept in biofloc and clear seawater and experimentally infected with White Spot Syndrome Virus DEPARTMENT OF BIOCHEMISTRY DEPARTMENT OF AQUACULTURE GRADUATE PROGRAM IN AQUACULTURE C. S. Valente 1 , K. O. Ortiz, A. P. M. Fraga, F. N. Vieira and M. R. F. Marques 2 ¹[email protected]; ²[email protected] Shrimp farming in biofloc system is considered as an economical and sustainable alternative to conventional rearing in clear seawater. Besides increasing productivity, its use may prevent diseases, as White Spot Syndrome, the most devastating viral disease of farmed shrimp. FEDERAL UNIVERSITY OF SANTA CATARINA (UFSC) BRAZIL 84 84 Biofloc Clear seawater WSSV experimental infection 100μl inoculum 5.3 x 10 4 virus. μl -1 Control groups 100μl sterile saline water * Shrimps monitored until 72h post infection (p.i.) 15 days of acclimatation Pleopod samples individual viral load by qPCR 48h gill samples transcription levels of genes by qPCR: Calreticulin, QM, Ubiquitin, SEC 61 and β-Tubulin Housekeeping genes: EF-1 and DEC 18S The aim of our study was to compare survival rates and transcription profile of target genes in Litopenaeus vannamei kept in biofloc (BT) versus clear seawater (CW) after experimental infection with White Spot Syndrome Virus (WSSV). Investigating the transcript profile of genes related to cellular defense and signaling pathways in shrimp may contribute to better understanding the effect of BT on metabolic and molecular responses toward pathogens. Moreover, we could also address distinct individual patterns of response toward viral infection, as suggested by our finding related to the comparative lower viral load detected in shrimp that survived WSSV challenge for 72h p.i. in BT. • Clinical signs lethargy, reddish body and decreased appetite, as expected • No mortality recorded up to 24h p.i. • General cumulative mortality was higher at 48h p.i. • Survival rate lower in BT • Average virus load lower in CW • Shrimp survivor in BT at 72h p.i. showed no detectable clinical signs • Transcript levels of target genes showed no significant difference between infected shrimp kept in BT versus CW Our findings could be related to WSSV virulence and to the initial viral load used to experimentally challenge shrimp; The lack of significant difference in the number of transcripts of the investigated target genes may indicate that gene expression was not affected by exposure to an aquatic environment with BT. Fig.5: WSSV infected shrimp kept in biofloc. Fig.6: WSSV infected shrimp kept in seawater. * Note the reddish color (particularly the telson) Fig.2: Detail of a shrimp tank with biofloc. Fig.1: Healthy shrimp. Fig.3: Healthy shrimp after feeding. Fig.4: Sampling (pleopod collection). All photos taken by authors. Proc. 407211/2012-8

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Transcription profile of target genes in the Pacific White Shrimp

(Litopenaeus vannamei) kept in biofloc and clear seawater and

experimentally infected with White Spot Syndrome Virus

DEPARTMENT OF BIOCHEMISTRY

DEPARTMENT OF AQUACULTURE

GRADUATE PROGRAM IN AQUACULTURE

C. S. Valente1, K. O. Ortiz, A. P. M. Fraga, F. N. Vieira and M. R. F. Marques2 ¹[email protected]; ²[email protected]

Shrimp farming in biofloc system is considered as an economical and sustainable alternative to conventional rearing in clear seawater. Besides increasing productivity, its use may prevent diseases, as White Spot Syndrome, the most devastating viral disease of farmed shrimp.

FEDERAL UNIVERSITY

OF SANTA CATARINA (UFSC)

BRAZIL

84 84

Biofloc Clear seawater

WSSV experimental infection 100µl inoculum 5.3 x 104 virus. µl-1

Control groups 100µl sterile saline water

* Shrimps monitored until 72h post infection (p.i.)

15 days of acclimatation

Pleopod samples individual viral load by qPCR

48h gill samples transcription levels of genes by qPCR: Calreticulin, QM, Ubiquitin, SEC 61 and β-Tubulin

Housekeeping genes: EF-1 and DEC 18S

The aim of our study was to compare survival rates and transcription profile of target genes in Litopenaeus vannamei kept in biofloc (BT) versus clear seawater (CW) after experimental infection with White Spot Syndrome Virus (WSSV).

Investigating the transcript profile of genes related to cellular defense and signaling pathways in shrimp may contribute to better understanding the effect of BT on metabolic and molecular responses toward pathogens. Moreover, we could also address distinct individual patterns of response toward viral infection, as suggested by our finding related to the comparative lower viral load detected in shrimp that survived WSSV challenge for 72h p.i. in BT.

• Clinical signs lethargy, reddish body and decreased appetite, as expected

• No mortality recorded up to 24h p.i. • General cumulative mortality was

higher at 48h p.i. • Survival rate lower in BT • Average virus load lower in CW • Shrimp survivor in BT at 72h p.i.

showed no detectable clinical signs • Transcript levels of target genes

showed no significant difference between infected shrimp kept in BT versus CW

Our findings could be related to WSSV virulence and to the initial viral load used to experimentally challenge shrimp; The lack of significant difference in the number of transcripts of the investigated target genes may indicate that gene expression was not affected by exposure to an aquatic environment with BT.

Fig.5: WSSV infected shrimp kept in biofloc.

Fig.6: WSSV infected shrimp kept in seawater.

* Note the reddish color (particularly the telson)

Fig.2: Detail of a shrimp tank with biofloc.

Fig.1: Healthy shrimp.

Fig.3: Healthy shrimp after feeding.

Fig.4: Sampling (pleopod collection).

All photos taken by authors.

Proc. 407211/2012-8