The objective of the present study was to investigate if dietary soluble non-starch polysaccharides (NSP) increase digesta viscosity, reduce nutrient digestibility and increase organ weights in African catfish. The fish (mean weight 80 g) were fed diets supplemented with the soluble NSP guar gum at three levels, 0 g kg )1 (GG0), 40 g kg )1 (GG4) and 80 g kg )1 (GG8). Guar gum inclusion significantly increased digesta viscosity in the proximal (GG0: 1.7 centipoise or cP; GG4: 84.9 cP; GG8: 98.3 cP) and distal (GG0: 1.9 cP; GG4: 109.8 cP; GG8: 66.4 cP) intestine. Apparent digestibility coefficients (ADC) were significantly lower for the GG8 diet than the GG0 diet (dry matter: 52% versus 69%; protein: 77% versus 90%; ash: 41% versus 54%; energy: 60% versus 77%). The ADC of dry matter and energy were significantly lower for the GG4 diet than the GG0 diet. The relative growth rate of metabolic weight (14.5-15.4 g kg )0.8 day )1 ) and feed conversion ratio (0.8) did not differ between diets. Fish fed the GG8 diet had a significantly higher somatic stomach index than GG0 fish (0.71% versus 0.65% body weight). The intestinal somatic index tended to increase with increasing guar gum supplementation (GG0: 1.08%; GG4: 1.23%; GG8: 1.59%). In conclusion, high digesta viscosities in the guar gum fed fish may explain the observed reduced nutrient digestibilities and increases in digestive organ weights.
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The effects of processing by autoclaving (AC), soaking (SK), short-term fermentation (S-TF, 4 d) and long-term fermentation (L-TF, 14 d) on the nutritional composition, amino acid profile and some antinutrients were determined for cottonseed meal (CSM), groundnut meal (GNM) and groundnut husk (GH) in this study. After processing, crude protein content improved by 11% after L-TF, and crude lipid content 25% after SK for CSM; crude protein content improved by 27% after S-TF and L-TF, and crude lipid content 13% after SK for GNM. Soaking and fermentation were shown to significantly increase essential amino acid contents by 44% (SK, methionine) in CSM and 46% in GNM (L-TF, histidine). Phosphorus content was reduced by 59% in CSM and 57% in GNM by L-TF. All processing techniques, with the exception of AC, reduced phytic acid and gossypol contents in CSM and GNM. It was concluded that SK and fermentation were simple, cost-effective, and efficient ways to improve the nutritional value of the selected oilseed by-products.
Mining of sand and stone from the coasts provides an inexpensive source of materials for the construction industry while providing income to contractors. However, these activities come at a cost to the coastal environment and pose a threat to the tourism industry along the Ghanaian coast. This paper identified the various types of coastal sand and stone mining activities, the level at which they are undertaken and covers the trends in coastal erosion along the coast of Cape Coast, Ghana. ArcGIS (ESRI, Redlands, CA, USA) and Digital Shoreline Analysis System (DSAS; ESRI) tools were used to determine short-term (2005-2012) coastline changes using 2005 and 2012 coastlines data. This study estimates that tippertruck-based beach sand mining activities alone account for the loss of about 285,376 m 3 /year of sand from the littoral zone in the Cape Coast area. It was also established that the average erosion rate for the Cape Coast area within the seven year period is 0.85 m/year with two areas recording high erosion rates of 4.35 m/year and 4.25 m/year. The study concludes that sand mining is the main cause of erosion along the coastline of Cape Coast.
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