Mahajanga, Madagascar
Mahajanga, Madagascar
Time filter
Source Type

Richard L.,French National Institute for Agricultural Research | Vachot C.,French National Institute for Agricultural Research | Breque J.,French National Institute for Agricultural Research | Blanc P.-P.,AQUALMA | And 3 more authors.
Journal of Experimental Marine Biology and Ecology | Year: 2010

This study evaluates the influence of both dietary protein and methionine on amino acid trans- and deamination (alanine aminotransferase, ALAT and glutamate dehydrogenase, GDH) in three tissues (muscle, hepatopancreas, gills) of the marine black tiger shrimp (Penaeus monodon). Shrimp (2.4. g) were fed one of the six semi-purified diets containing 14, 34 or 54% crude protein (% dry matter) with two levels of methionine (normal or 30% reduced) for 6. weeks. Both ALAT and GDH activities were the highest in the muscle. ALAT activity in muscle significantly decreased when feeding the low vs. high protein diets. Compared to those fed the intermediate protein level, GDH activity in muscle decreased (by 35%) when fed the low and increased (by 26%) when fed the high protein diets (P<0.05). A significant interaction between dietary protein and methionine was observed on GDH activity in gills which, due to the relative methionine deficiency, increased 4-fold at the intermediate protein level. In summary, our results demonstrate for the first time the capacity of up and downregulation of enzyme activity by dietary protein levels in the muscle of P. monodon, and the active role played by branchial tissue in ammoniogenesis in response to a relative indispensable amino acid (methionine) deficiency. © 2010 Elsevier B.V.

Tang K.F.J.,University of Arizona | Le Groumellec M.,AQUALMA | Lightner D.V.,University of Arizona
Diseases of Aquatic Organisms | Year: 2013

White spot syndrome virus (WSSV) is highly pathogenic to penaeid shrimp and has caused significant economic losses in the aquaculture industry around the world. During 2010 to 2012, WSSV caused severe mortalities in cultured penaeid shrimp in Saudi Arabia, Mozambique and Madagascar. To investigate the origins of these WSSV, we performed genotyping analyses at 5 loci: the 3 open reading frames (ORFs) 125, 94 and 75, each containing a variable number of tandem repeats (VNTR), and deletions in the 2 variable regions, VR14/15 and VR23/24. We categorized the WSSV genotype as {N125, N 94, N75, δX14/15, δX 23/24} where N is the number of repeat units in a specific ORF and δX is the length (base pair) of deletion within the variable region. We detected 4 WSSV genotypes, which were characterized by a full-length deletion in ORF94/95, a relatively small ORF75 and one specific deletion length in each variable region. There are 2 closely related genotypes in these 3 countries: {6125, del94, 375, δ595014/15, δ1097123/24} and {7125, del94, 375, δ595014/15, δ1097123/24}, where del is the full-length ORF deletion. In Saudi Arabia, 2 other related types of WSSV were also found: {6125, 794, 375, δ595014/15, δ1097 123/24} and {8125, 1394, 375, δ595014/15, δ1097123/24}. The identical patterns of 3 loci in these 4 types indicate that they have a common lineage, and this suggests that the WSSV epidemics in these 3 countries were from a common source, possibly the environment. © 2013 Inter-Research.

Richard L.,French National Institute for Agricultural Research | Blanc P.-P.,AQUALMA | Rigolet V.,AQUALMA | Kaushik S.J.,French National Institute for Agricultural Research | Geurden I.,French National Institute for Agricultural Research
British Journal of Nutrition | Year: 2010

We used a factorial approach to distinguish maintenance from growth requirements for protein, lysine and methionine in the black tiger shrimp, Penaeus monodon. Juvenile P. monodon (initial weight 24g) were fed during 6 weeks one of ten semi-purified diets based on casein and purified amino acids (AA) as N source. The diets contained four levels of crude protein (CP, from 5 to 54% DM diet) with two levels (% CP) of lysine or methionine (normal or 30% deficient). Requirements were determined using linear and non-linear regression models. We could thus obtain the first ever data on maintenance (N equilibrium) requirements for CP and AA in P. monodon. CP requirements for maintenance (45g/kg body weight (BW) per d) represented approximately 19% of the CP requirement for maximal N gain (239g/kg BW per d). The marginal efficiency of utilisation reached a maximum of 38% for N, 077 for lysine and 162 for methionine using N gain as response. Lysine requirements were 020g/kg BW per d for N maintenance and 140g/kg BW per d for maximal N gain. Methionine requirements were 011g/kg BW per d for N maintenance and 070g/kg BW per d for maximal N gain. The lysine (58%) and methionine (29%) requirements for maximal N gain, expressed as percentage of protein requirement, agree with literature data using a dose-response technique with smaller P. monodon. The observed interaction between dietary CP and methionine for N gain demonstrates that requirements for indispensable AA (expressed as % CP) cannot be evaluated separately from CP requirements. Copyright © The Authors 2010.

Han J.E.,University of Arizona | Tang K.F.J.,University of Arizona | Pantoja C.R.,University of Arizona | Lightner D.V.,University of Arizona | And 2 more authors.
Diseases of Aquatic Organisms | Year: 2016

Samples of microsporidia-infected shrimps exhibiting clinical signs of cotton shrimp disease were collected from Madagascar, Mozambique, and the Kingdom of Saudi Arabia from 2005 to 2014. The tails of the infected shrimps appeared opaque and whitish; subsequent histological examination revealed the presence of cytoplasmic inclusions and mature spores in tissues of the muscle, hepatopancreas, gills, heart, and lymphoid organ. PCR analysis targeting the small subunit rDNA (SSU rDNA) from infected samples resulted in the amplification of a 1.2 kbp SSU rDNA sequence fragment 94% identical to the corresponding region in the genome of the microsporidian Perezia nelsoni, which infects populations of Penaeus setiferus in the USA. Its SSU rDNA sequence was 100% identical among isolates from Madagascar and Saudi Arabia, indicating that shrimps from the Red Sea and Indian Ocean were infected with the same microsporidium, the novel Perezia sp. A 443 bp fragment of the SSU rDNA sequence was cloned, labeled with digoxigenin and subjected to an in situ hybridization assay with tissue sections of Perezia sp.-infected Penaeus monodon from Madagascar and Mozambique, and P. indicus from Saudi Arabia. The probe hybridized to the mature spores in the hepatopancreas and muscle from which the spores had been obtained for DNA isolation. This assay was specific, showing no reaction to another microsporidium, Enterocytozoon hepatopenaei (EHP), infecting the hepatopancreas of shrimp P. stylirostris cultured in SE Asian countries. We also developed an SSU rDNA-based PCR assay, specific for the novel Perezia sp. This PCR did not react to EHP, nor to genomic DNA of shrimp and other invertebrates. © Inter-Research 2016.

Loading AQUALMA collaborators
Loading AQUALMA collaborators