Theses and Dissertations


Title: Effects of dietary xanthophylls (astaxanthin and zeaxanthin) on growth, survival, and pigmentation of Australian red claw crayfish (Chrerax quadricarinatus)

Name: Wei, Dong

Degree: MS

Chair: David B. Rouse

Resides:

University: Auburn University

Location: Auburn, Alabama

Date: 2004

Pages: 49

Keywords: Xanthrophylls, diet, growth, survival, pigmentation, Australian red claw crayfish, Cherax quadricarinatus

Abstract:

Carotenoids function as a colorant, provitamin A and an antioxidant. Hence, it is considered a required nutrient and pigmentation enhancement in diets for aquatic animal culture. There is limited information on the effects of carotenoids (e.g. astaxanthin and zeaxanthin) in practical diets for Crustacea. Hence, the objective of this study was to clarify and contrast further the influence of dietary xanthophylls (astaxanthin and zeaxanthin) on growth, survival, and pigmentation of Australian red claw crayfish, Cherax quadricarinatus. Three growth trials were conducted using an indoor recirculating system, practical containing 32% protein and 6% lipid and newly released hatchlings were conducted. In the first growth trial, the basal diet and diets supplemented with graded levels (20, 40, 80, 120, or 160 ppm) of zeaxanthin was evaluated. After 42 days, no significant differences were observed in final mean weights, percent weight gain or survival of red claw crayfish. Final mean weights of the red claw crayfish ranged from 0.51 to 0.64 g. Survival of the red claw crayfish ranged from 68% to 88%. Presumably due to cross contamination of samples, there were no significant differences observed between dietary treatments for mean astaxanthin concentrations in the carapace. In a second trial newly released hatchling red claw crayfish were fed diets containing graded levels (0, 20, 40, 80, 120, or 160 ppm) of astaxanthin. After 42 days, no significant differences were observed in final mean weights, percent weight gain or survival of red claw crayfish. Final mean weights ranged from 0.29 to 0.39 g. Survival ranged from 64% to 88%. Significant differences were observed between dietary treatments for mean astaxanthin concentrations in the carapace, which ranged from 1.65 ppt to 8.18 ppt for crayfish offered diets containing 0 and 120 ppm astoxanthin, respectively. In a third trial, the basal and diets containing (40 and 80 ppm) astaxanthin or zeaxanthin were offered over a 56-day period. At the conclusion of the growth trial, no significant differences were observed in final mean weights, percent weight gain or survival of red claw crayfish offered the various diets. Final mean weights of the red claw crayfish ranged from 0.44 to 0.73 g. Survival ranged from 27% to 43%. Significant differences were observed between dietary treatments for astaxanthin concentrations in the carapace, which ranged from 0.48 ppt to 8.45 ppt. A fourth experiment was conducted using juvenile red claw reared in an outdoor flow through culture system. In addition to a control diet without carotenoid supplements, juvenile red claw were fed an astaxanthin-supplemented diet (80 ppm) and a zeaxanthin- supplemented diet (80 ppm). There were no significant differences in final mean weight, percent weight gain, FCR, or survival of red claw crayfish offered the various diets. Final mean weights of the red claw crayfish ranged from 11.5 to 12.2 g. FCR ranged from 2.2 to 2.8. Survival ranged from 87% to 93%. Mean astaxanthin concentrations in the carapace of red claw were not influenced by dietary treatments. They ranged from 10.14 ppt to 12.47 ppt. In the present study, there are no significant differences in terms of growth and survival for newly released and juvenile red claw crayfish due to the supplementation of astaxanthin and zeaxanthin to the diet. From a pigmentation standpoint, zeaxanthin produced slightly higher levels of astaxanthin concentrations in the carapace as compared to astaxanthin, although they were not significant differences. Increasing supplemental astaxanthin or zeaxanthin levels can cause the increase of astaxanthin concentration in the carapace till a saturation point (about 120 ppm in this study for red claw crayfish). However, in the outdoor growth trial, the supplementation of carotenoids did not result in an increased pigmentation. It is likely that natural productivity was adequate to supply carotenoids. Hence, when pigmentation is limited

Download: Download

203 Swingle Hall | Auburn, Alabama 36849 | (334) 844-4786 |
Website Feedback | Privacy | Copyright ©