Objective: To observe the effect of feeding on different pig tissues on the development of Chrysomya megacephala larvae.
Methods: About 200 larvae each were reared on four different substrates, i.e. pig's brain, liver, muscle and a mixture of minced pork muscle and fat (7 : 3) at a constant temperature of 25 degrees C. Length and weight of larvae and pupae were measured at 12 h interval 16 h after eclosion. 10 larvae or pupae were collected each time. The time of development, mortality, and sex ratio of adults were recorded.
Results: Three replicated experiments showed that the larvae fed on liver grew slowly, time of reaching maximum length and weight was delayed for about 24-36 h, and the duration of larva development was longer than that of other groups (P<0.01). The mean maximal larval length in mixture group [(14.89 +/- 0.39) mm] was statistically shorter than that of brain group, muscle group and liver group, [(17.81 +/- 0.54), (16.94 +/- 0.43) and (17.14 +/- 0.27) mm, respectively] (P<0.01). The mean maximal larval weight in liver group [(73.5 +/- 6.8) mg] and mixture group [(63.0 +/- 5.4) mg] was statistically lighter than brain group [(91.2 +/- 7.5) mg] and muscle group [(86.3 +/- 7.3) mg] (P<0.01). The pupal length in mixture group was statistically shorter than that of other 3 groups (P<0.01). The pupal weight of mixture group and liver group was statistically lighter than that of brain group and muscle group (P<0.01). The larval and pupal mortality of mixture group [(9.8 +/- 3.1)% and (8.9 +/- 3.1)%] was statistically higher than that of brain group [(5.5 +/- 3.1)% and (4.6 +/- 1.5)%], muscle group [(4.7 +/- 2.2)% and (3.8 +/- 2.0)%] and liver group [(5.4 +/- 2.3)% and (4.8 +/- 1.7)%] (P<0.01). There was no significant difference in the sex ratio among the four groups (P>0.05).
Conclusion: The development duration of the larvae fed on liver is longer than other groups. The body length and weight of larvae and pupae fed on mixture diet are less than other groups with higher mortality.