Digestibility of diets containing different soybean meals in Atlantic cod (Gadus morhua); comparison of collection methods and mapping of digestibility in different sections of the gastrointestinal tract

The purpose of the experiment was to evaluate effects of partial replacement of fish meal with soybean meal on digestibility in Atlantic cod and effects of biotechnological processing of soybean meal. Other objectives were to find out if apparent digestibility in cod was affected by age, temperature and/or faecal sampling methods, and to map digestion and absorption patterns along the intestinal tract for different age classes and diets. A control diet with fish meal as the main protein source (FM), a diet with 24% of crude protein from conventional extracted soybean meal (SBM), and a diet with 24% of crude protein from a bioprocessed soybean meal (BP-SBM) were used. Yttrium oxide was added as an inert marker for digestibility determination. The diets were fed to duplicate groups of 534 g (1-year-old) and 1750 g (2-year-old) cod in seawater. Faeces were stripped from the distal-most section (distal chamber) of the intestine after 48 and 84 days of feeding. In addition, intestinal contents were removed by dissection after 84 days. The dissected intestine was divided into 5 sections and contents were analysed separately. Dietary soy did not alter the viscosity of the digesta. The replacement of fish meal protein with soybean protein reduced the apparent digestibility of crude protein, fat, energy and almost all amino acids, independent of type of soybean meal processing. Larger fish had higher digestibility of starch, ash and several amino acids than smaller fish. A temperature decrease from 9.1 °C at feeding day 48 to 6.8 °C at day 84 resulted in lower digestibility of starch, ash and several amino acids. Absorption of amino acids was quantitatively terminated in the distal part of the mid intestine when feeding the soy-containing diets, but continued into the distal chamber when feeding the FM diet. Absorption of fat was completed in the proximal part of the mid intestine when feeding the soy-containing diets, but continued into the middle part of the mid intestine when feeding the FM diet. Soy did not affect absorption pattern of starch along the intestinal tract. Faecal sampling by dissection resulted in higher apparent digestibility of macronutrients than stripping in the 2-year-old cod, and higher apparent digestibility of protein in the 1-year olds.     

Utilization of carotenoids from various sources by rainbow trout: muscle colour,carotenoid digestibility and retention

Rainbow trout (Oncorhynchus mykiss) with a mean (sd) weight of 120 (2) g were fed diets supplemented with astaxanthin extracted from the yeast Phaffia rhodozyma (OY1 = 50 mg carotenoids kg^–1 feed, OY2 = 100 mg carotenoids kg^–1 feed), astaxanthin (AX = 100 mg astaxanthin kg^–1 feed) and canthaxanthin (CX = 100 mg canthaxanthin kg^–1 feed) for 4 weeks. Muscle analyses at the end of the experiment indicated a significantly higher carotenoid concentration in the AX group, while CX and OY1 groups were similar in spite of the differences in dietary concentration. The measure of total muscle colour difference (E^* _ab) between initial samples and 4 week ones was higher for the AX fish group but showed no significant difference between OY1, OY2, and CX. The hue and the reflectance ratio (R₆₅₀:R₅₁₀) of fish muscle increased in proportion to carotenoid intake. Digestibility (ADC) of yeast astaxanthin in OY1 and OY2 groups was significantly higher than that in the AX group. Canthaxanthin ADC was about one sixth of that of astaxanthin (AX group). Carotenoid retention in the muscle, expressed as a percentage of carotenoid intake, was higher for the AX group than that recorded for OY1 and OY2. According to ADC, carotenoid retention showed a marked lower value for the CX group. Muscle retentions were similar for astaxanthins from both sources.     

Astaxanthin digestibility as affected by ration levels for Atlantic salmon, Salmo salar

The objective of this study was to determine the effect of feed intake on the apparent digestibility coefficient (ADC) of astaxanthin including the major geometrical E/Z-isomers in Atlantic salmon (Salmo salar). Atlantic salmon (50 per pen, initial weight 2 kg) were kept in 125 m³ sea pens equipped with an excess feed collection system to monitor and quantify accurate feed intake, and subjected to three treatments in triplicate. All salmon were fed the same diet supplemented with 47 mg astaxanthin per kg. Two treatments were fed full or restricted rations corresponding to 100 or 40% of apparent satiation, respectively, with a switch in ration between two consecutive feeding periods (14 and 3 d, respectively), whereas the control treatment was fed to 100% of apparent satiation during both periods. The corresponding feed intakes were 0.45 and 0.16% of biomass for salmon fed 100% or 40% of apparent satiation, respectively. Faeces were collected by stripping at the end of each feeding period and ADCs of astaxanthin were determined by an indirect method using yttrium oxide (Y₂O₃) as an indigestible marker. Feed intake and astaxanthin ADC were negatively correlated (R² = 0.64; p = 0.0001). Astaxanthin ADC was 1.5 times higher at the low compared to the high ration level (p < 0.05), but due to the low feed intake the total amount of digested astaxanthin was only about 50% of that in fish fed to satiation. The ADCs of the all-E and 13Z-isomers of astaxanthin were similar and considerably higher than for 9Z-astaxanthin (p < 0.05). The amount of digested astaxanthin/TGC (estimated thermal growth coefficient) decreased with increasing feed intake. Estimates of astaxanthin retention indicated that a higher feed intake cause a lower muscle concentration of astaxanthin compared to that obtained at low feed intakes due to the lower digestibility. Blood samples were collected at the end of the second feeding period to examine possible relationships between plasma carotenoids, feed intake and ADC. Salmon without faeces in the hindgut had a lower plasma astaxanthin concentration compared to salmon with faeces in the hindgut (p < 0.05). In conclusion, feed intake and astaxanthin ADC are negatively correlated, and may thus explain reductions in muscle retention of Atlantic salmon.     

Chemical Composition and In Vitro Dry Matter and Organic Matter Digestibility of Triticale Forage

Triticale (X Triticosecale Wittmack) cultivars Council and Morrison were planted in mid-September (early planting) and mid-October (late planting) in 1984 at the Alabama A &: M University-experiment station for studying organic matter digestibility. The plants were harvested at the tillering, milk and dough stages and samples were subjected to proximate analyses and in vitro digestibility tests. A 1,100 lb Hereford steer fitted with a permanent ruminal fistula was used as the rumen fluid donor. In vitro dry matter digestibility (IVDMD) and in vitro organic matter digestibility (IVOMD) were determined by Moore's modification of the two-stage digestion technique of T illy and T erry (1963). Triticale cultivar Council was comparable to Morrison for phosphorus (P), dry matter (DM), ceil wall content, IVDMD and IVOMD. Crude protein (CP) and ash content were significantly higher for Morrison than for Council , while gross energy (GE) was significantly higher for Council than for Morrison. Both early and late plantings showed similar levels of DM, GE, P and cell wall constituents. However, CP and ash content were higher for early planting than late planting. The tillering stage was consistently higher than the milk or dough stages for CP, ash, P, calcium (Ca), IVDMD and IVOMD. The results indicate that the milk stage was superior to the tillering or dough stages in DM and cell wall content. Results from this study showed no significant differences in digestibilities for two triticale cultivars and planting dates. Based on the higher DM content at the milk stage, it seems that milk stage in triticale would be more acceptable as a forage than the tillering or dough stage.     

引流黑熊对三种不同蛋白质水平日粮消化利用的比较研究

作者设计了蛋白质水平为 2 3 1 0 %、2 6 98%和 32 56%的三种日粮 ,分别饲喂Ⅰ、Ⅱ、Ⅲ组手术引流黑熊 ,比较研究 3组受试黑熊对日粮蛋白质的消化利用率。结果表明Ⅰ、Ⅱ、Ⅲ组受试黑熊蛋白质消化率分别为 70 47%、77 1 4%和 77 99% ,其中Ⅱ组与Ⅲ组间无显著差异(P >0 1 ) ;Ⅰ组与Ⅱ组和Ⅲ组间差异显著 (P <0 1 ) ;Ⅱ、Ⅲ组受试黑熊蛋白质消化率显著高于Ⅰ组 (P <0 0 5)。在上述 3种日粮蛋白质水平下 ,3组受试黑熊均处于氮的正平衡状态 ,Ⅰ、Ⅱ、Ⅲ组受试黑熊食入总氮利用率分别为 2 6 96%、41 72 %和 37 69% ,3组间有显著差异 (P<0 0 5)。     

日粮淀粉水平对绒山羊纤维物质消化性能的影响

9只带有瘤胃瘘管、十二指肠近端瘘管和回肠末端瘘管的内蒙古白绒山羊随机分为3组,研究了日粮精粗比(3∶7)相近的条件下,提高日粮淀粉水平对纤维物质消化性能的影响。结果表明,随日粮淀粉水平的提高,日粮纤维在胃区及全消化道消化率也随之下降,而在大肠的消化率有上升的趋势,但各组间差异均不显著(P>0.05)。     

Comparative nutritive value of winged bean (Psophocarpus tetragonolobus (L) DC) and other legumes grown in Tanzania

Chemical analyses and feeding experiments using rats were conducted to evaluate the nutritive value of winged bean and other legumes (soyabean, green gram, bambarra nuts, pigeon peas, field beans, cow peas) sources grown in Tanzania. Proximate analyses showed that the composition of winged bean was similar to soyabean, while the composition of the other legumes differed considerably. This was also the case for antinutritional constituents and minerals. As to the amino acid composition, the lysine level was high with the highest value in winged bean (7.5 g/16 g N). However, the concentration of methionine and cystine was low which limits their protein quality. Another important amino acid, threonine, was generally high, especially in winged bean (4.3 g/16 g N). With exception of field bean, true protein digestibility was above 80%, soyabean having the highest value (90.7%). The biological value was also highest in soyabean (76.1%) followed by winged bean (69.9%). Utilizable protein was high in soyabean (28.8%) and somewhat lower in winged bean (23.4%). Energy digestibility was around 80%, soyabean having the highest value of 85.8%. The study findings support the idea that winged bean is a good alternative plant protein source in Tanzania.     

Cultivar and processing effects on the pasting characteristics,tannin content and protein quality and digestibility of cowpea (Vigna unguiculata)

Four popular West African local cultivars of cowpea (Vigna unguiculata), with distinctly different seed coat colors, were evaluated for their relative amylograph pasting characteristics, condensed tannin content, in vitro protein digestibility and Tetrahymena protein efficiency ratio (t-PER). The effects of roasting and dehulling on these properties were also determined. There were wide variations in the hot paste viscosity characteristics of the different cultivars studied. The raw cowpea flour samples exhibited maximum paste viscosities ranging between 260 Brabender Units (BU) for the Mottled cultivar and 460 BU for the cream-colored Blackeye cultivar. Cowpea cultivars with the greatest peak viscosities showed low stabilities to extended cooking. Roasting depressed paste viscosity properties of all the cowpea cultivars studied. Tannin concentrations were 0.3–6.9 and 7.2–116 mg CE/g flour from whole cowpea seeds and seed coats respectively, increasing with intensity of seed color. Although dehulling removed 98% of the tannin content of raw cowpeas, improvement in protein quality as a result of dehulling was observed for only the highly-pigmented Maroon-red variety. Roasting significantly improved digestibility and more than doubled the t-PER of all cowpea cultivars studied. Roasted cowpeas possess adequate nutritional and functional qualities as protein supplements in cereal-based weaning foods. However, it appears that dehulling is necessary to enhance the nutritional quality of the highly pigmented cultivars of cowpea.     

Comparison of acid-detergent lignin,alkaline-peroxide lignin,and acid-detergent insoluble ash as internal markers for predicting fecal output and digestibility by cattle offered bermudagrass hays of varying nutrient composition

Camelina sativa is an oil seed crop which can be grown on marginal lands. Camelina seed oil is rich in omega-3 fatty acids (>35%) and γ-tocopherol but is also high in erucic acid and glucosinolates. Camelina meal, is the by-product after the oil has been extracted. Camelina meal was fed to 28 d old weaned pigs at 3.7% and 7.4% until age 56 d. The camelina meal supplements in the soy based diets, improved feed efficiency but also significantly increased the liver weights. Gene expression analyses of the livers, using intra-species microarrays, identified increased expression of phase 1 and phase 2 drug metabolism enzymes. The porcine versions of the enzymes were confirmed by real time PCR. Cytochrome 8b1 (CYP8B1), aldehyde dehydrogenase 2 (Aldh2), and thiosulfate transferase (TST) were all significantly stimulated. Collectively, these genes implicate the camelina glucosinolate metabolite, methyl-sulfinyldecyl isothiocyanate, as the main xeniobiotic, causing increased hepatic metabolism and increased liver weight.