Impact of Anisakis pegreffi Infection on Gonadal Health and Gonadosomatic Index of European Hake (Merluccius merluccius)

Abstract

Parameters belonging to the physical status and gonadal size of certain fish provide crucial information for assessing both the productivity and fecundity of declining fish populations. These parameters are vulnerable to the negative impacts of disease agents such as internal or systemic parasites. Although parasitic diseases might influence these parameters, the literature investigating these pathophysiological alterations is scanty. Therefore, the current study represents one of the scarcest studies that document the possible link between parasitism, gonadal health, and the growth of European hake ( Merluccius merluccius ). Screening of imported European halves indicated a relatively high prevalence of Anisakis pegreffi Larvae 3 infestation, with an 80% prevalence rate, a mean intensity of 24.4, and a mean abundance of 19.5. However, the prevalence of Anisakid larvae infection in native fish was 36% with a mean intensity of 7.36 and mean abundance of 2.65.The current research revealed remarkable ovarian pathology that involved several forms of degenerative changes in ovarian tissues. Such gonadal pathologies were attributed to the damaging effect of the retrieved Anisakis pegreffi Larvae 3. Gonadosomatic index of both heavily infected imported / native hakes was relatively impacted by the progressive gonadal pathology resulting from Anisakis pegreffi L3 infection. Morphometric measurements of the gonads and body have revealed that, gonadosomatic index of both heavily infected imported / native hakes was relatively impacted by the progressive gonadal pathology resulting from Anisakis pegreffi L3 infection.