Nutritional, physiological, and histological responses in Atlantic salmon, Salmo salar L. fed diets with genetically modified maize

Abstract

The objective of this study was to evaluate whether standard fish meal diets prepared with increasing levels of genetically modified (GM; 150 and 300 g kg−1) maize (event MON810®) as a starch source, showed any nutritional or physiological adverse effects on Atlantic salmon, Salmo salar L. postsmolt. The diets with low or high inclusions of GM maize and its near‐isogenic parental line (nongenetically modified; nGM maize), were balanced with Suprex maize (Reference) to obtain compositional equivalency of diet starch, sugars and all other nutrients. Total starch level in all diets was 160 g kg−1. After 82 days of feeding, fish growth was high in all groups, however fish fed the GM maize showed slight but significant lower feed intake, which was followed by slight but significant lower specific growth rate and final body weights, compared with fish fed nGM maize, none of the groups varied significantly from fish fed the Reference diet. There was no variation in feed conversion ratios (FCR), protein and lipid efficiency ratios (PER and LER), or protein‐ and lipid‐productive values (PPV and LPV) in this study. No significant effect of maize type was detected on apparent digestibility coefficients (ADC) of dry matter, protein or lipid. Hematological analysis and plasma nutrients varied within normal ranges for Atlantic salmon in all diet groups, except for somewhat elevated aspartate aminotransferase (ASAT) values in all groups. Hepatosomatic index (HSI) with values ranging from 1.37 to 1.60, was significantly higher for the high GM maize group compared with the high nGM maize group but not when compared with the Reference diet group. Lowered spleen (SSI) and head‐kidney somatic indices (H‐KSI) were registered when fed GM compared with nGM maize, the Reference treatment was however, equal to both. Distal intestine somatic index (DISI) was significantly higher for GM maize‐fed fish compared with nGM maize‐fed fish, but not significantly different from the Reference diet group. Histological evaluation of the mid‐ and distal intestine, liver, spleen and head‐kidney did not reveal any diet‐related morphological changes. Maltase activities in the mid‐ and distal intestinal tissue homogenates were affected by diet, the fish fed high GM maize having higher activities compared with high nGM maize‐fed fish. Leucine aminopeptidase (LAP) and alkaline phosphatase (AP) activities were not affected by diet. Sodium‐dependent d‐glucose uptake in brush border membrane vesicles (BBMV) isolated from pyloric caeca of fish fed high GM maize was significantly higher than that found in fish fed the analogous diet with high nGM maize. Based on the present findings, the conclusions made are: Atlantic salmon smolts fed GM maize (event MON810®), its near‐isogenic parental line and suprex maize (Reference diet), all resulted in high growth rates, ADC and feed utilization. Health, when evaluated by means of mortality (low), normal ranges of blood and plasma parameters, except somewhat elevated ASAT values and minor variations in organ siz...

Apparent digestibility coefficients of several protein sources, and replacement of fishmeal by porcine meal in diets of Japanese seabass, Lateolabrax japonicus, are affected by dietary protein levels

“…2004; Geurden, Kaushik & Corraze 2008). The haematological parameters determined (TAG, cholesterol, glucose, BUN, ALAT and ASAT) were similar to those of the other teleost, such as European seabass and carp ( Cyprinus carpio ) (Lemaire, Drai, Mathieu, Lemaire, Carrière, Giudicelli & Lafaurie 1991; Svobodová, Vykusová, Modrá, Jarkovský, Smutná 2006), but ALAT and ASAT of all the groups were significantly lower than those of Amur sturgeon ( Acipenser schrenckii ), Chinese sturgeon ( A. sinesis ) and Atlantic salmon ( Salmo salar L.) (Shi, Li, Zhuang, Nie & Long 2006; Hemre, Sagtad, Bakke‐Mckellep, Nanieli, Acierno, Maffia, Frøystad, Krogdahl & Sanden 2007). Besides, these parameters in fish showed a large annual variety (Fernandez & Planas 1980) and might be affected by bacterial infection (Acerete, Espinosa, Josa & Tort 2009).…”

Distal intestinal gene expression in Atlantic salmon (Salmo salarL.) fed genetically modified maize

“…In the latter study, starch inclusion levels were lower compared to the present study. In the current experiment in which maize was included up to 300 g kg −1 of dietary dry matter, spleen size and RBC were not altered, but changes were found in pyloric tissue transport of glucose (Hemre et al. 2007) .…”

“…The investigations reported here were part of a larger feeding trial in which Atlantic salmon were fed diets with the starch source (Suprex maize, Condrico AB, the Netherlands) replaced by increasing levels of GM maize (event MON810) or the untransformed near‐isogenic parental line of MON810 (non‐GM maize). Two other reports on nutritional, physiological and histological responses as well as the gene expression of stress proteins are previously published (Hemre et al. 2007; Sagstad et al.…”

Exploring the nutritional demand for essential fatty acids by aquaculture species

“…As with other GM products, an assessment of the benefits and risks associated with their use will provide some clarity on this issue (Glencross et al. 2003c; Hemre et al. 2007; European Food Safety Authority 2008).…”

“…As with other GM agricultural resources there is likely to be concern and scepticism associated with the release of such oils. As with other GM products, an assessment of the benefits and risks associated with their use will provide some clarity on this issue (Glencross et al 2003c;Hemre et al 2007;European Food Safety Authority 2008).…”