20079
Although we did not measure metabolism directly , seeing that the transcription level of many genes encoding enzymes involved in the mitochondrial respiratory chain and oxidative phosphorylation were down - regulated in the highly polluted site suggests that pollutants may have a significant effect on energy metabolism in these fish .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None