Effect of food restriction on the energy metabolism of the Chinese bulbul（Pycnonotus sinensis）

Food resources play an important role in the regulation of animals’ physiology and behavior. We investigated the effect of short-term food restriction on metabolic thermogenesis of Chinese bulbuls（Pycnonotus sinensis） by measuring changes in body mass, body fat, basic metabolic rate（BMR）, and organ mass of wild-caught Chinese bulbuls from Wenzhou, China. Short-term food restriction induced a significant decrease in body mass and body fat but body mass returned to normal levels soon after food was no longer restricted. Food restriction caused a significant reduction in BMR after 7 days（P〈0.05）, which returned to normal levels after food restriction ceased. Log total BMR was positively correlated with log body mass（r2=0.126, P〈0.05）. The dry masses of livers and the digestive tract were higher in birds that had been subject to temporary food restriction than in control birds and those subject to continual food restriction（P〈0.001 and P〈0.05, respectively）. There was also significant differences in the dry mass of the lungs（P〈0.05）, heart（P〈0.01）, and spleen（P〈0.05） in birds subject to short-term food restriction compared to control birds and those subject to continual food restriction. BMR was positively correlated with body and organ（heart, kidney and stomach） mass. These results suggest that the Chinese bulbul adjusts to restricted food availability by utilizing its energy reserves, lowering its BMR and changing the weight of various internal organs so as to balance total energy requirements. These may all be survival strategies that allow birds to cope with unpredictable variation in food abundance.

The role of leptin in striped hamsters subjected to food restriction and refeeding

Food restriction （FR） and refeeding （Re） have been suggested to impair body mass regulation and thereby making it easier to regain the lost weight and develop over-weight when FR ends. However, it is unclear if this is the case in small mammals showing seasonal forging behaviors. In the present study, energy budget, body fat and serum leptin level were measured in striped hamsters that were exposed to FR-Re. The effects of leptin on food intake, body fat and genes expressions of several hypothalamus neuropeptides were determined. Body mass, fat content and serum leptin level decreased during FR and then increased during Re. Leptin supplement significantly attenuated the increase in food intake during Re, decreased genes expressions of neuropepetide Y （NPY） and agouti-related protein （AgRP） of hypothalamus and leptin of white adipose tissue （WAT）. Hormone-sensitive lipase （HSL） gene expression of WAT increased in leptin-treated hamsters that were fed ad libitum, but decreased in FR-Re hamsters. This indicates that the adaptive regulation of WAT HSL gene expression may be involved in the mobilization of fat storage during Re, which partly contributes to the resistance to FR-Re-induced overweight. Leptin may be involved in the down regulations of hypothalamus orexigenic peptides gene expression and consequently plays a crucial role in controlling food intake when FR ends.

Effect of Maternal Food Restriction on the Uterus of Female Rats from the First and Second Generation

Postnatal life is affected by changes in fetal development due to adverse events. The present study examined the effect of maternal food restriction on uterine structure and capacity in female rats from the first and second generations (FR1 and FR2) before and after puberty. Pregnant rats were fed ad libitum (Control, C) or maintained under food-restriction conditions (50%FR) during pregnancy. After delivery, all groups were given free access to food. Females from the first generation (FR1) were divided into two subgroups for either uterine dissection or to produce the next generation (FR2). Similar to FR1, FR2 females were exposed to maternal food restriction following the same procedure. FR2 females were also assigned into two subgroups for either uterine dissection or for mating to examine pregnancy outcomes. Uteri from the C, FR1 and FR2 groups were dissected at 4 weeks of age (before puberty) or at 8 weeks of age (after puberty) to evaluate uterine weight and uterine horn length. Tissues were stained with eosin and haematoxylin for examination vialight microscopy. The results showed that food restriction did not affect uterine weight or uterine horn length in FR1 and FR2 females before puberty. However, there were effects of maternal food restriction on uterine weight and length at 8 weeks of age. Uterine weight and uterine horn length were significantly reduced in the FR1 and FR2 groups compared with the values of the controls. This was associated with changes in pregnancy outcomes. Litter size was not affected in the FR1 group;however, litter weight was significantly reduced, leading to an 18% reduction in pup weight at birth. Unlike with FR1 litters, the size of FR2 litters was significantly reduced, leading to a lower degree of pup body weight reduction at birth (only 7%). The gestational length was normal in FR1 females but was significantly decreased in FR2 females. No histopathological changes were observed. These results showed that the uterus was affected by maternal food restriction. It seemed that FR2 females had a different reproductive strategy: they tended to reduce litter size to maintain pup weight at birth. In conclusion, maternal food restriction affects the uteri of the first and second generation. Females from the FR1 and FR2 groups followed different reproductive strategies according to their previous experience with exposure to intrauterine food restriction.

High temperature slows down growth in tobacco hornworms （Manduca sexta larvae） under food restriction

When fed ad libitum （AL）, ectothermic animals usually grow faster and have higher metabolic rate at higher ambient temperature. However, if food supply is limited, there is an energy tradeoff between growth and metabolism. Here we hypothesize that for ectothermic animals under food restriction （FR）, high temperature will lead to a high metabolic rate, but growth will slow down to compensate for the high metabolism. We measure the rates of growth and metabolism of 4 cohorts of5th instar hornworms （Manduca sexta larvae） reared at 2 levels of food supply （AL and FR） and 2 temperatures （20 and 30 ℃）. Our results show that, compared to the cohorts reared at 20 ℃, the ones reared at 30 ℃ have high metabolic rates under both AL and FR conditions, but a high growth rate under AL and a low growth rate under FR, supporting this hypothesis.

Characteristics and outcomes of avoidant/restrictive food intake disorder in Japanese elementary-school students on total parenteral nutrition

The clinical outcomes of adolescents with avoidant/restrictive food intake disorder(ARFID)remain unclear.Furthermore,no report has compared the characteristics of ARFID and restricting-type anorexia nervosa(R-AN)in elementary-school students on total parenteral nutrition(TPN).This study retrospectively reviewed inpatients diagnosed with ARFID or R-AN between 2005 and 2019.Patients with ARFID(two boys and seven girls)and R-AN(13 girls)were hospitalized because of rapid physical deterioration,and nutrition therapy was continued without withdrawal.The ARFID group exhibited significantly lower body weights at admission than the R-AN group and gained an average of 6.5 kg during hospitalization;furthermore,the monthly weight gain during hospitalization was significantly higher,and no relapse was observed.Early physical improvement in ARFID resulted in good recovery.In conclusion,TPN can be easily introduced to patients with ARFID,in whom aversive eating is a concern,and is a suitable treatment for ARFID.