Acrosome breakdown in Leptodactylus chaquensis is described: during this process acrosome enlarges, becomes round‐shaped and finally disrupts. Low tonicity media (0.025 M sucrose and 1/10 Holtfreter's solutions) favor acrosome breakdown and sperm fertility loosing. High tonicity media (0.250 M sucrose and Holtfreter's solutions) maintain acrosomes in an unreacted stage and sperm fertilizing capacity is preserved. Sperm motility does not seem to be a sufficient condition for the sperm to fertilize and also does not seem to be related with acrosome breakdown. The presence of lectins in the incubation media does not modify the time‐course of acrosome breakdown.

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Ensuring lumpfish health and welfare in salmon farms is vital to reduce the high mortality rates reported and to guarantee a high delousing efficiency. Recent observations of farmed lumpfish livers have shown colours ranging from pale (colours 1 and 2), through bright orange (colours 3 and 4), to dark reddish-brown (colours 5 and 6), some of which may be related to welfare condition. To characterize the status of lumpfish deployed in four Faroese salmon farms, several welfare indicators were assessed: a weight-length relationship, scoring of external physical damage, and after dissection, stomach content and liver colour scoring. Liver samples were weighed, stored and analysed for lipid content, lipid classes, total pigments, fatty acid profile and histopathology to explain the differences between the mentioned liver colours. Bright orange livers, liver colours 3 and 4, were related to increased levels of carotenoid pigments rather than levels of lipids and appear to reflect good fish welfare. However, dark reddish-brown colours, liver colours 5 and 6, were associated with very low levels of triacyl glycerides in the liver, indicating use of lipid reserves and poor welfare condition. Histopathology confirmed that the dark reddish-brown livers, liver colours 5 and 6, formed a distinct group. Thus, liver colour was shown to be a good welfare indicator and should be monitored in farms.