Seasonal Changes And Gender Differences In Energy Intake Of Yangtze Finless Porpoise (Neophocaena Phocaenaides Asiaeorientalis) In Captivity

From August 2009 to August 2010, the law of seasonal changes of energy metabolism and gender difference of four Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis) in captive were studied. During the study, a big sum of Yangtze finless porpoise'food intake data, water temperature records and also physical examination records which applied by the trainers who works in The Wu Han BaiJi Dolphinarium have been analized. Finally, we found some meaningful conclusions.The main results are summarized as the following:1. The influence of temperature on food intake. In captivity, changes in food intake under the effect of temperature are obviously. Till year 2004, the maturation of female porpoise JJ which stabilized the changing relation between temperature and food intake in all individuals. When the water temperature in the swimming pool changes in 17²6°C scope, all individuals keep the monthly total food intake in the scope of 110¹40Kg, according to the feature of Temperature neutral zone in homoeothermic animals, we named such a temperature range as Temperature neutral zone.When temperature under the neutral zone's critical low temperature, the finless porpoise's food intake was rising sharply,the maximum of food intake(190Kg) won't arise until the water temperature in the pool got to 9°C; When temperature higher than the critical high temperature,the food intake was obviously decreased, Until the water in the pool get to the highest temperature(28°C) ,the lowest food intake was 110Kg.2. Seasonal variation regularity of energy intake. In captivity, because of seasonal changes in water surrounded the finless porpoise in different seasons there was a significant difference in energy intake rate. Energy intake rate in spring is the lowest(the minimum of femal was4.47 KjKg^-1d^-1 and the male's5.04 Kj Kg^-1d^-1 ) and the highest is in winter. The variation of energy intake rate can reflects how much the finless porpoise's need for food intake. According to the result of this paper, we suggest supplying the fresh fish for the finless porpoise.3. Gender differences in energy intake rate. In captivity, energy intake rate has obvious gender differences, the Oneway ANOVA result shows the relation between the male finless porpoise AF and the two female finless porpoise YY and JJ reaching an extremely remarkable level. May is the turning point of gender difference,the highest average value of energy intake rate of YY during Jan to May was 7.59 Kj Kg^-1d^-1,then is AF(6.65 Kj Kg^-1d^-1),the lowest energy intake rate is JJ(5.79 Kj Kg^-1d^-1); The average energy intake rate of AF was 5.64 Kj Kg^-1d^-1.After May, this value is much higher than the two female finless porpoise YY and JJ.