Two separate 7‐week feeding trials were conducted to evaluate the use of mealworm, Tenebrio molitor, as an alternative protein source for African catfish, Clarias gariepinus. In Experiment 1, six isonitrogenous (40% crude protein) and isoenergetic (14.64 kJ g−1) practical diets were formulated. The fish meal component of the diets was progressively substituted at 0, 20, 40, 60, 80 and 100% with mealworm meal. The experimental diets were fed to triplicate groups of catfish fingerlings (mean initial weight of 5.1 ± 0.2 g) at 4% body weight day−1. Growth performance and feed utilization efficiency of catfish fed diets with up to 40% replacement of fish meal with worm meal were not significantly different (P > 0.05) compared to fish fed the control diet without any worm meal. Catfish fed diets with up to 80% replacement of fish meal with the worm meal still displayed good growth and feed utilization efficiency. In Experiment 2, the nutritive value of mealworms was compared with a commercial catfish pellet. Three dietary treatments consisting of fish fed catfish pellets only, catfish pellets and mealworms, and mealworms only were tested. Catfish fed solely on mealworms displayed a slight depression in growth performance but when fed in combination with the catfish pellets grew as well or better than fish fed the commercial catfish pellet only. In both experiments, mealworms, whether used as such or transformed into a dry meal, were found to be highly palatable to the African catfish. Catfish fed mealworm‐based diets also tend to have significantly higher lipids in their carcass. Results indicate that mealworm was an acceptable alternative protein source for the African catfish.

The properties of the hydrogen-bonded polymer blends of poly(4-vinylphenol) and poly(2-ethoxyethyl methacrylate) are presented. Spectroscopic techniques such as 13C solid-state NMR and FT-IR are used to probe specific interactions of the blends at various compositions. Spectral features from both techniques revealed that site-specific interactions are present, consistent with a significant degree of mixing of the blend components. Changes in chemical shift and line shape of the phenolic carbon and carbonyl resonances in the 13C CPMAS spectra of the blends as a function of composition are interpreted as resulting from changes in the relative intensities of two closely overlapped signals. A quantitative measure of hydrogen-bonded carbonyl groups using 13C NMR has been obtained which agreed well with the results from FT-IR analyses. It is also shown that 13C NMR can be used to measure the fraction of hydroxyl groups associated with carbonyl groups, which was not possible previously using FT-IR due to extensive overlapping of bands in the hydroxyl stretching region. The results of measurements of 1H T 1 and 1H T 1 ρ indicate that PVPh and PEEMA are intimately mixed on a scale less than 2−3 nm.

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ABSTRACT:The Mooney scorch times of three rubber blends [epoxidized natural rubber (ENR) 50/SMR L, ENR 50/styrene butadiene rubber (SBR), and Standard Malaysian Rubber SMR L/SBR] were studied in the temperature range of 120-160ЊC using an automatic Mooney viscometer. N-Cyclohexyl-2-benzothiazyl sulfenamide was used as the accelerator, and the rubber formulation was based on the conventional vulcanization system. Results for the blends investigated indicate that a negative deviation of scorch time from the interpolated value was observed, especially for temperatures lower than 130ЊC. This observation was attributed to the induction effect of the ENR 50 in the ENR 50/SMR L and ENR 50/SBR blends to produce more activated precursors to crosslinks, thus enhancing interphase crosslinking. To a lesser extent, SMR L also exhibited such an induction effect in the SMR L/SBR blend. At 120ЊC, maximum induction effect occurred at around a 40% blend ratio of ENR 50 and SMR L in the respective blends. For the filled stock at 140ЊC, carbon black exhibited less effect on the scorch property of the blends compared to silica.