The accumulation of nutrients during diapause preparation is crucial because any lack of nutrition will reduce the likelihood of insects completing diapause, thereby decreasing their chances of survival and reproduction. The fall webworm, Hyphantria cunea, diapause as overwintering pupae and their diapause incidence and diapause intensity are regulated by the photoperiod. In this study, we test the hypothesis that photoperiod influences energy reserve accumulation during diapause preparation in fall webworm. We found that the body size and mass, lipid and carbohydrate content of pupae with a short photoperiod during the diapause induction phase were significantly greater than those of pupae with a relatively short photoperiod, and the efficiency of converting digested food and ingested food into body matter was greater in the short-photoperiod diapause-destined larvae than the relatively short-photoperiod diapause-destined larvae. We also observed higher lipase and amylase activities in short-photoperiod diapause-destined larvae relative to the counterparts. However, no obvious difference was found in protein and protease in the pupae with a short photoperiod during the diapause induction phase and short-photoperiod diapause-destined larvae compared with the counterparts. Therefore, we conclude that the energy reserve patterns of diapausing fall webworm pupae are plastic and that short-photoperiod diapause-destined larvae increase their energy reserves by improving their feeding efficiency and increase their lipid and carbohydrate stores by increasing the lipase and amylase activities in the midgut.

The work comments on the results of four experiments on biological responses of growing turkeys to fresh or oxidized fat applied in a concentrate mixture in amounts from 2% at the beginning (1–4 weeks) to 5% in the end period of fattening (13–16 weeks). The content of fat with a high peroxide value (50–150 meq O2/kg), which contained simultaneously a higher content of selenium (0.3 mg/kg), vitamin E (30–40 mg/kg) and vitamin A (1200–15000 IU/kg) caused reduction in body weight gain of turkeys, mainly as a result of lowered feed intake. Enriching diets with fat of a very high degree of oxidation (100–150 meq O2/kg) did not result in worsening of the turkeys' health condition, but considerably lowered their vitamin E reserves. Symptoms of muscular dystrophy and changes in biochemical and enzymatic indices in serum and liver were not observed. However, a decrease in the activity of lactic dehydrogenase in liver lesion of hepatocytes was noted, that was partially confirmed in microscopic assay and ultrastructural characteristics of liver. The rise in temperature (from 23°C to 30°C) in the rearing pens reduced the effect of the turkey feeding, while not, at the same time increasing a negative effect of oxidized fat on the fattening results. Products of fat oxidation increased the birds' susceptibility to virus infections causing haemorrhagic intestinal inflammation.