Efecto diferencial de la intoxicación crónica por aflatoxina B1 en el crecimiento y en la incidencia de lesiones hepáticas en truchas diploides y triploides. atenúa los efectos de una intoxicación aguda por la aflatoxina B1 (AFB1, se intoxicaron con AFB1 pura, tres grupos de diez pollos cada uno ( mb/kg pc, IP. ANÁLISIS DE AFLATOXINAS Y OCRATOXINA A EN. ALIMENTOS .. intoxicación aguda por micotoxinas en el hombre es bajo o moderado en.
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Triploid trout has been considered to be more resistant po diploid trout to many diseases and to some adverse aquaculture conditions. Considering the common problems with animal food contamination by aflatoxins, the purpose of this research was to compare the incidence of liver lesions and growth performance in triploid and diploid trout O.
Five samples in each group were monthly sacrificed during one year. The histopathological analyses were performed with liver slides stained with hematoxylin and eosin. The comparative analyses of the growth performance showed significant difference between control and treated diploid, suggesting ppor aflatoxin B1 affects the growing of diploid trout. In triploid groups this aspect was not observed. The histopathological analyses indicated that triploid trout is more resistant to aflatoxin B1, since this group did not present neoplastic lesions.
Diploid fishes however, showed 4 samples with neoplastic lesion. The triploid treated group had preneoplastic lesion, but with minor incidence and slower progression than diploid trout. Rainbow trout, triploidy, aflatoxin, hepatocarcinogenesis. Trucha arco iris, triploidia, aflatoxina, hepatocarcinogenesis.
The triploidization has been shown to be a promising technique in fish farming because triploid fishes, being sterile animals, are spared from the physiologic stress of the sexual maturation and reproductive behavior Benfey, Also, they are not subjected to the immunodepressive state commonly associated to the reproductive process. Their mortality is reduced and they show better growing rates after the first year of life and show less aggressive behavior than diploid fishes.
These features open new possibilities in meat fish market or in their use in fish farms dedicated to sport fishing which is, an expanding economic activity in the last decade. Several studies have been developed in order to increase the knowledge of the metabolic activity and behavior of triploid cells in many organs and tissues since the triploidization technique was first applied to aquaculture Graham et al.
The objective of this study was to compare the productivity of triploid fishes vs diploid fishes, taking into account parameters such as growth rate, weight gain and susceptibility to diseases Kim et al. Although triploid fishes had been evaluated in several adverse conditions found in aquaculture and under different stress situations, their response to aflatoxin contaminated food has not been investigated.
The usual commercial fish food is composed by cereal grains corn, soybean, wheat. The effect of the ingestion of aflatoxin B1 contaminated fish food on the growth performance and on the incidence and evolution of hepatic lesions in triploid and diploid rainbow trout are compared in tis study.
After the fry reached 8 grams of average weight, both diploid and triploid specimens were separated in the following groups: All groups received their respective experimental food twice a day for 12 months. Thirty days after the beginning of the experiment 5 animals from each group were sacrificed by immersion in 1: The procedure was repeated monthly until the end of the experiment. Blood samples were taken from the caudal blood vessels and blood smears were prepared.
The triploidy was confirmed by measuring the main axis of erythrocytes nuclei per glass slide without staining Benfey et al.
The measurements were obtained aflatosinas a light microscope with a graded eyepiece Leitz. The celomatic cavity was open by a ventrolongitudinal incision and the liver was exposed and studied pof locu before being removed. Sections 6 mm thick were cut, stained by hematoxilin-eosin method for further histopathologic study.
The criteria established by Arana were applied to establish three basic situations describing the incidence of liver preneoplastic lesions in hepatic section focal and nodularcharacterized by the histopathologic inspection: A dichotomous classification was applied to neoplastic lesions: The comparison between the biometric data of the different groups took into account their temporal component and a regression analysis was applied to each group of monthly average values.
A statistical test analysis of variance was aflatoxnias to verify the difference between the regression lines p Beiguelman, The statistical analysis of the incidence of liver lesions was carried out using the computer programs SAS and Minitab, taking the number of animals showing lesions and their occurrence per quarter as parameters.
In data analysis, the null hypothesis was the effect of treatment. The Wald test Mood et al. It was observed if the probability of the test value analyzed was under a table value X 2. In the case this probability was aflatodinas than athe null hypothesis was rejected and the difference between the effect of treatment was accepted as significant.
In our work, the comparative analysis of the biometric parameters revealed a significant difference between the DC intoxicacikn and the other groups. The small difference observed in the lines did not result in a significant difference between TC and TT aflatoxinqs.
The histopathologic study of the liver of the control groups DC and TC showed the typical morphology described for the species throughout the experiment and no one kind of lesion was identified Fig. Diploid and triploid fishes treated with aflatoxin, DT and TT groups, presented several kind of lesions that are characteristics of intoxication and carcinogenesis process in liver induced by aflatoxin, such as the occurrence of foci of basophilic cells-BF Figs.
The foci aflatoixnas basophilic cells and nodule of basophilic cells were considered preneoplastic lesions.
Preneoplastic lesions were found in both diploid and triploid animals, but the lesions occurrence and progression were reduced in triploid specimens. It may then be observed in Graphs 34 and 5 that basophilic cells foci BF and basophilic cells nodules BN appeared later in triploid than in diploid. It may be noted in these graphs that the hepatocarcinogenesis process is slow in triploid and while TT group had BF type lesions, DT group showed predominance of BN type lesion.
Neoplastic lesions were observed in DT group, afflatoxinas in the last quarter, when four diploid animals showed hepatocellular carcinoma Figs. Aflatoxin B1 is an important member of the aflatoxin family due to its highly toxic and carcinogenic properties Wogan, Such effects have stimulated a great number of scientific investigations, most of them dealing with rainbow trout on account of its high sensibility to this mycotoxin.
A revision from Bailey et al. Particularly, triploid trout was less used in aflatxinas experiments Thorgaard et al. Our results indicate that AFB1 effectively reduced the growth rate and weight gain of diploid animals.
The triploid fishes however, were resistant to this effect. The gap between the growth performance of DC group and the intoxicaxion fishes as a whole may be ascribed to the usual slower growth of triploid fishes along the first year of life when compared to diploid fishes, a fact that has been experimentally demonstrated by other authors. This situation is usually reversed when diploid trouts reach the sexual maturity period Aflatoxnias, Liver section from trout treated with AFB1 showing a basophilic cells nodule.
A basophilic cells intoxicaciom may be noted in liver section from trout treated with AFB1. Detail of a basophilic cell nodule showing basophilic cells characteristics of this kind of lesion. Figures of mitosis short arrows and apoptosis long arrows are indicted. Liver section from a trout exposed to aflatoxin B1 showing acidophilic foci and a small basophilic foci. A vacuolated foci composed by cells with macro and micro vacuolization in cytoplasm can be observed in this section of liver from a trout treated with AFB1.
Detail of vacuolated foci composed by cells with micro vacuolization in cytoplasm. Part of a hepatocellular carcinoma surrounded by anaplastic cells arrowheads is showed in this liver section aflatoxxinas diploid trout treated with AFB1.
Detail of a section of hepatocellular carcinoma. A proliferating ductal area surrounded by desmoplasic tissue and micronodules composed by small basophilic cells may be observed in this field. This graphic shows the adjusted lines to the weight measurement means obtained along the experiment and includes the mathematic expression by which they are represented, as well as the determination coefficient R 2.
Representative graphic of the adjusted lines to the total length measurement means obtained along the experiment and includes the mathematic expression by which they are represented, as well as aflatoxinsa determination coefficient R 2. Quarterly evaluation of the incidence of basophilic cells foci BF and basophilic cells nodules BNtaking in account the occurrence of 1 lesion by hepatic area studied in diploid trout DT and triploid TT treated with AFB1 contaminated food, considering the total number of animals with lesions in 15 samples analyzed during the quarter period.
Quarterly evaluation pot the incidence of intoxicacino cells foci BF and basophilic cells nodules BNtaking in account the occurrence of 2 lesions by hepatic area studied in diploid trout DT and triploid TT treated with AFB1 contaminated food, considering the total number of animals with lesions in 15 samples analyzed during the quarter period.
Quarterly evaluation of the incidence of basophilic cells foci BF and basophilic cells nodules BNtaking in account the occurrence of 3 lesions by hepatic area studied in diploid trout DT and triploid TT treated with AFB1 contaminated food, aflatosinas the total number of animals with lesions in 15 samples analyzed during the quarter period. Presumptive preneoplastic lesions, characteristically described wflatoxinas the hepatocarcinogenesis process Bannasch,were noted in AFB1 treated groups DT and TT: However, as Hendricks et al.
We then emphasized the occurrence of the preneoplastic lesions formed by basophilic cells as a mean to evaluate the hepatocarcinogenesis process.
The characterization of focal lesions and nodular lesions on the basis of lesion size adopted here is the same one used by Bannasch, that is why we aflayoxinas the most common classification used in hepatocarcinogenesis experiments.
However, Hendricks et al. In fact, basophilic cells intoxixacion precede basophilic cells nodule, as it has been demonstrated by intoxcacion carcinogenesis studies Bannasch, Interesting data about the lesions evolution may still be inferred from Graph. These results suggest that some BF lesions may have regressed or that they have a very slow evolution thus, reducing the progression of the hepatocarcinogenesis process in triploid fishes.
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With respect to the neoplastic lesion itself observed only in diploid trout, the aflatoxinqs of neoplastic lesion after 9 or 12 months of AFB1 exposure has already been reported in the literature for rainbow trout Bailey et al.
Our data indicate that triploid animals are more resistant to the hepatotoxic effects of AFB1 in the food. Similar results were obtained by Thorgaard et al. These authors observed a intxoicacion incidence of neoplastic aflatoxinsa in the different target organs of triploid trout, that was variable to the carcinogen applied. The specific reasons for this resistance of triploid trout to the carcinogenic activity of AFB1 and other carcinogenic substances are not intoxicadion clear.
However, to elucidate this hypothesis, or others that may be elaborated to explain the hepatocarcinogenesis in triploid trout, as greater expression of genes related to detoxifying aflatlxinas, it will be necessary to carry out more experiments with a methodology that could evaluate the degree of involvement of these molecules or the role of the mechanisms associated to triploidy.
Durante doce meses, mensualmente, ontoxicacion ejemplares de cada grupo fueron anestesiados y sacrificados. En truchas triploides no se observaron diferencias entre pesces del grupo control y los pesces tratados. We thank Luiz Roberto da Silva and Antonio Donizeti da Silva for care and feeding of the fish, Rosana Aparecida da Silva for her assistance with the necropsies of the animals, Baltazar Pereira de Paula for his assistance during the contamination of the food and Viviane de Araujo Guerra for her assistance with the statistical analyses.
Relationship between ration size and dietary protein level varying at the expense of carbohydrate and lipid in triploid brown trout fry, Salmo trutta. Fish models for environmental carcinogenesis: Sequential cellular changes during chemical carcinogenesis. Preneoplastic lesions as end points in carcinogenicity testing.
The physiology of triploid salmonids in relation to aquaculture. Acute stress in triploid rainbow trout Oncorhynchus mykiss and brook trout Salvelinus fontinalis. Use of erythrocyte measurements to identify triploid salmonids. Genetic variation in growth parameters until commercial size in diploid and triploid freshwater rainbow trout Salmo trutta. Protein synthesis in different tissues of mature rainbow trout Salmo gairdneriR.
Their implications for human and animal health. Effect of triploidy on blood oxygen content of Atlantic salmon. Effects of triploidy on rainbow trout myogenesis in vitro.