Studies on the preservation of crab processing waste and evaluation of the quality of the protein from crab waste

• Main Author: Joseph, Mercy A. D
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-1996
• Subjects: Animal sciences; Aquaculture; Aquatic sciences; Fish production; Livestock
• ISBN: 0591081628; 9780591081626

Three experiments were conducted to determine the effect of different chemicals on the preservation of crab waste at room temperature. In Exp. 1,.2 and.4% NaOCl and $\rm H\sb2O\sb2$ were used and the waste was stored for 17 d. In Exp. 2, NaCl (10%), NaNO$\sb2$ (1%), NaOCl (.4%), NaN$\sb3$ (.065%), KNO$\sb3$ (.1%), Tert butyl hydroperoxide (TBHP) (50 ppm), and I$\sb2$ (25 ppm) were used. After mixing with the chemicals the waste was stored for 21 d. In Exp. 3, the waste was treated with NaCl (10%), NaNO$\sb2$ (1%) and NaN$\sb3$ (.065%) and the mixtures were kept for 20, 30 and 40 d. In the first experiment the waste treated with.4% NaOCl preserved better than for the other treatments, with lower (P $<$.05) NH$\sb3$ and trimethylamine (TMA). In Exp. 2, treatment with NaCl, NaNO$\sb2$ and NaN$\sb3$ did not produce any change in the physical characters of the crab waste. The TMA, indole and NH3 were lower (P $<$.05) and no H$\sb2$S was detected in the waste treated with those chemicals. In Exp. 3, treatment with NaCl did not alter the physical characteristics of crab waste. The waste had lower (P $<$.05) NH$\sb3$, TMA and indole on d 20, 30 and 40 than those treated with NaNO$\sb2$ and NaN$\sb3$. Protein separated from crab waste was evaluated by in vitro and in vivo with chicks. Treatment with 1% KOH for 1 h gave maximum (P $<$.05) protein recovery. Approximately 25 kg of crab waste protein supplement (CWPS) were recovered, which contained on an average 43.2% CP, 30.5% ether extract and 17.8% total ash. In vitro protein digestibility was similar to that for soybean meal (SBM). A feeding experiment was conducted to evaluate the quality of CWPS with 180, 1-d old broiler male chicks. Crab waste protein supplement replaced 0, 25 and 50% SBM protein. The five dietary treatments were: A - 0% CWPS fed ad libitum; B - 25% CWPS diet fed ad libitum; C - 50% CWPS diet fed ad libitum; D - 25% CWPS diet pair-fed to diet C; and E - 0% CWPS diet pair-fed. The birds were fed for 21 d and the excreta were collected during the last 3d. Blood samples and pancreas weights were obtained from three birds from each pen. Linear decreases (P $<$.05) were recorded in body weight gain, and gain/feed with increasing levels of CWPS in the ad libitum and pair-fed chicks. The N and energy retention decreased linearly with increased CWPS in the ad libitum fed birds. Average weight of pancreas increased linearly with increased levels of CWPS. The uric acid index was higher for chicks fed the control diet and lowest for those fed 25% CWPS diet (quadratic effect, P $<$.05). It is concluded that the poor performance of chicks fed CWPS diets may be due to lower feed intake and digestibility of CWPS, and that CWPS can substitute for SBM protein at 25% level in the diets of chicks with little effect on performance.