Encapsulation of soybean meal with fats enriched in palmitic and stearic acids: effects on rumen-undegraded protein and in vitro intestinal digestibility.

Fat coating of soybean meal (SBM) can reduce its protein degradability in the rumen, but the encapsulation of SBM with palmitic (PA) and stearic acids (SA) has not yet been investigated, despite both fatty acids are common energy sources in dairy cow diets. This study aimed to evaluate the effects of applying a novel method, using either 400 or 500 g fat/kg (treatments FL40 and FL50, respectively), which was enriched in PA and SA at different ratios (100:0, 75:25, 50:50, 25:75 and 0:100), on physical and chemical characteristics, ruminal degradability, solubility and in vitro intestinal protein digestibility (IVIPD) of the obtained products. Encapsulation of SBM in fat resulted in greater mean particle size and lower bulk density and protein solubility than unprotected SBM (USBM). Treatment FL50 resulted in increased (p < 0.01) rumen-undegraded protein (RUP) compared to USBM. There were no differences in RUP of SBM when different PA: SA ratios were used. The mean RUP content of treatments FL40 and FL50 (306 and 349 g/kg, respectively) was greater compared to USBM (262 g/kg, p < 0.05), but lower than that for a standard heat-treated SBM (431 g/kg). Values of IVIPD did not differ among SBM, heat-treated SBM and FL40 and FL50 samples, all being greater than 97.8%. In conclusion, encapsulation of SBM with fats enriched in PA and SA proved to be effective in reducing protein solubility and increasing RUP without depressing protein digestibility in the intestine. For validation of the method, in vivo research to investigate the effects of these products on the production of dairy cows is warranted.

Postprandial nutrient-sensing and metabolic responses after partial dietary fishmeal replacement by soyabean meal in turbot (Scophthalmus maximus L.).

In this study, we chose a carnivorous fish, turbot (Scophthalmus maximus L.), to examine its nutrient-sensing and metabolic responses after ingestion of diets with fishmeal (FM), or 45% of FM replaced by soyabean meal (34·6% dry diet) balanced with or without essential amino acids (EAA) to match the amino acid profile of FM diet for 30 d. After a 1-month feeding trial, fish growth, feed efficiency and nutrient retention were markedly reduced by soyabean meal-incorporated (SMI) diets. Compared with the FM diet, SMI led to a reduction of postprandial influx of free amino acids, hypoactivated target of rapamycin signalling and a hyperactivated amino acid response pathway after refeeding, a status associated with reduced protein synthesis, impaired postprandial glycolysis and lipogenesis. These differential effects were not ameliorated by matching an EAA profile of soyabean meal to that of the FM diet through dietary amino acid supplementation. Therefore, this study demonstrated that the FM diet and SMI diets led to distinct nutrient-sensing responses, which in turn modulated metabolism and determined the utilisation efficiency of diets. Our results provide a new molecular explanation for the role of nutrient sensing in the inferior performance of aquafeeds in which FM is replaced by soyabean meal.

Gut morphology and hepatic oxidative status of European sea bass (Dicentrarchus labrax) juveniles fed plant feedstuffs or fishmeal-based diets supplemented with short-chain fructo-oligosaccharides and xylo-oligosaccharides.

The effects of short-chain fructo-oligosaccharides (scFOS) and xylo-oligosaccharides (XOS) on gut morphology and hepatic oxidative status were studied in European sea bass juveniles weighing 60 g. Fish were fed diets including fishmeal (FM diets) or plant feedstuffs (PF diets; 30 FM:70 PF) as main protein sources (control diets). Four other diets were formulated similar to the control diets but including 1 % scFOS or 1 % XOS. At the end of the trial, fish fed PF-based diets presented histomorphological alterations in the distal intestine, whereas only transient alterations were observed in the pyloric caeca. Comparatively to fish fed FM-based diets, fish fed PF diets had higher liver lipid peroxidation (LPO), superoxide dismutase (SOD) and catalase (CAT) activities, and lower glutathione peroxidase, glutathione reductase and glucose 6-phosphate dehydrogenase activities. In fish fed the PF diets, prebiotic supplementation decreased SOD activity and XOS supplementation further decreased CAT activity. In fish fed the FM diets, XOS supplementation promoted a reduction of all antioxidant enzyme activities. Overall, dietary XOS and scFOS supplementation had only minor effects on gut morphology or LPO levels. However, dietary XOS reduced antioxidant enzymatic activity in both PF and FM diets, which indicate a positive effect on reduction of hepatic reactive oxygen species production.

Soyabean glycinin depresses intestinal growth and function in juvenile Jian carp (Cyprinus carpio var Jian): protective effects of glutamine.

This study investigated the effects of glycinin on the growth, intestinal oxidative status, tight junction components, cytokines and apoptosis signalling factors of fish. The results showed that an 80 g/kg diet of glycinin exposure for 42 d caused poor growth performance and depressed intestinal growth and function of juvenile Jian carp (Cyprinus carpio var. Jian). Meanwhile, dietary glycinin exposure induced increases in lipid peroxidation and protein oxidation; it caused reductions in superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activities; and it increased MnSOD, CuZnSOD, GPx1b and GPx4a mRNA levels, suggesting an adaptive mechanism against stress in the intestines of fish. However, dietary glycinin exposure decreased both the activity and mRNA levels of nine isoforms of glutathione-S-transferase (GST) (α, µ, π, ρ, θ, κ, mGST1, mGST2 and mGST3), indicating toxicity to this enzyme activity and corresponding isoform gene expressions. In addition, glycinin exposure caused partial disruption of intestinal cell-cell tight junction components, disturbances of cytokines and induced apoptosis signalling in the distal intestines>mid intestines>proximal intestines of fish. Glycinin exposure also disturbed the mRNA levels of intestinal-related signalling factors Nrf2, Keap1a, Keap1b, eleven isoforms of protein kinase C and target of rapamycin/4E-BP. Interestingly, glutamine was observed to partially block those negative influences. In conclusion, this study indicates that dietary glycinin exposure causes intestinal oxidative damage and disruption of intestinal physical barriers and functions and reduces fish growth, but glutamine can reverse those negative effects in fish. This study provides some information on the mechanism of glycinin-induced negative effects.

Effects of soyabean meal- or whey-based diets on lipid metabolism in weaned piglets.

The present study aimed to test the hypothesis that dietary protein source influences lipid metabolism-related parameters weaned piglets. The effects of soyabean meal (SB) and whey proteins (WP) on gene expression of several genes involved in the lipogenic process in liver, visceral (VAT) and subcutaneous (SAT) adipose tissues, plasma insulin concentration and fatty acid (FA) profile were investigated in 18 weaned piglets. Weaned piglets were fed one of two diets containing either SB or WP as the main protein source. Following a 10-h fasting period, plasma insulin concentration and FA profile were assessed at 56 and 72 days of age, whereas gene expression in liver, VAT and SAT was assessed at 72 days of age. Plasma insulin concentration was not affected by diet, although it was 40% lower in SB fed pigs. The SB pigs had lower 14:0 (p < 0.01) and higher 18:3n-3 (p < 0.001) levels in plasma in comparison with WP pigs. However, these changes were attributed to background differences in the dietary FA profile and not to a direct protein source effect. Gene expression of sterol regulatory element-binding protein 1 (SREBP-1) in liver and VAT were lower (p < 0.01 and p < 0.05, respectively) in SB compared to WP fed piglets, but no differences occurred in SAT. No changes were observed in sterol regulatory element-binding protein 2, liver X receptor, peroxisome proliferator-activated receptors α and γ and plasminogen activator inhibitor 1 mRNA levels, either in liver or in adipose tissues. In conclusion, dietary protein source, accompanied likely by side alterations in the dietary composition, affects lipid metabolism in pigs through the downregulation of SREBP-1, which is a crucial determinant of lipogenic process.

Sclerocarya birrea caffra nut meal as a substitute to soyabean meal: Effects on growth performance, feed intake and utilisation and viscera macromorphometry of blue-helmeted guinea fowl.

Imported soyabean meal (SBM) is the major dietary protein (DP) source for the sub-Saharan African poultry industry making poultry production costly. Therefore, alternative locally available DP sources are required. We evaluated the potential of locally available Marula nut meal (MNM) to substitute SBM in Guinea fowl (GF) diets by determining its effects on growth, feed intake (FI) and utilisation and viscera macromorphometry. Five grower diets wherein, on a CP basis, MNM substituted SBM at 0, 25, 50, 75 and 100% were formulated. Thirty-eight 4-week-old keets (n = 7 - 8), each individually housed in a cage, were randomly assigned to grower diets, and fed for 5 weeks and then transferred to corresponding finisher diets and fed for 3 weeks. Induction and weekly body mass, daily FI, and terminal body mass (TBM), body mass gain (BMG), average daily gain (ADG) and feed conversion ratio (FCR) were determined. On slaughter, viscera masses, small and large intestines lengths, tibiae and femora indices were determined. In week 2 of the grower phase GF fed diet 3 (50% MNM CP) had the highest weekly BMG and ADG (P < 0.05) and in week 5 GF fed diet 5 (100% MNM CP) had the highest FI (P < 0.05). Dietary MNM did not affect the GF's BMG, ADG, FI and FCR during weeks 1, 3 and 4 of the grower phase. In week 3 of the finisher phase GF fed diet 3 (50% MNM CP) had the highest (P < 0.05) FCR. Dietary MNM had no effect (P > 0.05) on the trial BMG, ADG and FI of the GF but GF reared on grower and finisher diets 3 (50% substitution of SBM CP) had the highest (P < 0.05) FCR. MNM had no effect on tibiae and femora masses, lengths, and mass: length ratios and viscera macromorphometry of the GF. We conclude that MNM can, on a CP basis, substitute SBM, in GF grower and finisher diets at 25%, 75% and 100% without compromising growth, FI and utilization and viscera of GF.

Effects of Dietary Ximenia caffra Meal on Nutrient Intake, Digestibility, Nitrogen Balance and Growth Performance in Sprague Dawley Rats Modelling Monogastrics.

BACKGROUND AND OBJECTIVE: The sub-saharan livestock feed industry depends on imported soyabean meal (SBM) as a dietary protein source in feeds thus making livestock production costly. This calls for the search and development of local dietary protein sources. Using Sprague Dawley rats to model monogastric animals, this study evaluated the potential of Ximenia caffra kernel meal (XCKM) to substitute SBM as a dietary protein source in feeds. MATERIALS AND METHODS: Five diets were formulated wherein XCKM replaced SBM on a crude protein basis at 0, 25, 50, 75 and 100%. In the digestibility trial, 20 adult male SD rats were randomly assigned to the 5 diets. After a 12-day adaptation period feed and nutrient intake, faeces and urine output were determined over a 5-day collection period. Apparent Total Tract Digestibility (ATTD) of nutrients and nitrogen absorption and retention were determined. In the growth trial, 40 weanling male SD rats were randomly assigned to the five dietary treatments and fed for 38 days. The rats were weighed twice weekly. Following euthanasia, gastrointestinal viscera were harvested and their macro-morphometry determined. Linear growth was determined from tibiae and femora indices. RESULTS: In adult rats dietary XCKM had no (p>0.05) effect on ATTD of nutrients. At 100% substitution of SBM, XCKM increased (p<0.05) faecal nitrogen loss while at 75% substitution level it increased (p<0.05) nitrogen retention. In growing SD rats, although dietary XCKM had no effect (p>0.05) on the terminal body and empty carcass mass and viscera macro-morphometry, at 100% SBM substitution, it significantly compromised (p<0.05) body mass gain and average daily gain. Femora and tibiae mass and seed or index significantly decreased (p<0.05) with increased dietary XCKM. CONCLUSION: The XCKM could replace SBM as a dietary protein source in adult SD rat feeds without compromising ATTD digestibility of nutrients and nitrogen utilization thus it could be speculated that XCKM can be utilized as a dietary protein source in feeds of mature monogastrics. Caution must be exercised in using XCKM in grower rat diets as its use at higher inclusion levels compromised growth performance and long bone health.

Bacterial translocation and in vivo assessment of intestinal barrier permeability in rainbow trout (Oncorhynchus mykiss) with and without soyabean meal-induced inflammation.

The primary aim of this experiment was to evaluate the intestinal barrier permeability in vivo in rainbow trout (Oncorhynchus mykiss) fed increasing levels of soyabean meal (SBM). The relationship between SBM-induced enteritis (SBMIE) and the permeability markers was also investigated. Our results showed that the mean score of morphological parameters was significantly higher as a result of 37·5 % SBM inclusion in the diet, while the scores of fish fed 25 % SBM or lower were not different from those of the fish meal-fed controls (P < 0·05). SBMIE was found in the distal intestine (DI) in 18 % of the fish (eleven of sixty): ten in the 37·5 % SBM-fed group and one in the 25 % SBM-fed group. Sugar markers in plasma showed large variation among individuals probably due to variation in feed intake. We found, however, a significant linear increase in the level of plasma d-lactate with increasing SBM inclusion level (P < 0·0001). Plasma concentration of endotoxin was not significantly different in groups with or without SBMIE. Some individual fish showed high values of endotoxin in blood, but the same individuals did not show any bacterial translocation. Plasma bacterial DNA was detected in 28 % of the fish with SBMIE, and 8 % of non-SBMIE fish (P = 0·07). Plasma concentration of d-lactate was significantly higher in fish with SBMIE (P < 0·0001). To conclude, SBMIE in the DI of rainbow trout was associated with an increase in bacterial translocation and plasma d-lactate concentration, suggesting that these permeability markers can be used to evaluate intestinal permeability in vivo.

Aspergillus oryzae S2 alpha-amylase production under solid state fermentation: optimization of culture conditions.

Aspergillus oryzae S2 was assayed for alpha-amylase production under solid state fermentation (SSF). In addition to AmyA and AmyB already produced in monitored submerged culture, the strain was noted to produce new AmyB oligomeric forms, in particular a dominant tetrameric form named AmyC. The latter was purified to homogeneity through fractional acetone precipitation and size exclusion chromatography. SDS-PAGE and native PAGE analyses revealed that, purified AmyC was an approximately 172 kDa tetramer of four 42 kDa subunits. AmyC was also noted to display the same NH2-terminal amino acid sequence residues and approximately the same physico-chemical properties of AmyA and AmyB, to exhibit maximum activity at pH 5.6 and 60 °C, and to produce maltose and maltotriose as major starch hydrolysis end-products. Soyabean meal was the best substitute to yeast extract compared to fish powder waste and wheat gluten waste. AmyC production was optimized under SSF using statistical design methodology. Moisture content of 76.25%, C/N substrate ratio of 0.62, and inoculum size of 10(6.87) spores allowed maximum activity of 22118.34 U/g of dried substrate, which was 33 times higher than the one obtained before the application of the central composite design (CCD).

Intestinal B(0)AT1 (SLC6A19) and PEPT1 (SLC15A1) mRNA levels in European sea bass (Dicentrarchus labrax) reared in fresh water and fed fish and plant protein sources.

The objective of the present study was to examine the effect of diets with descending fish meal (FM) inclusion levels and the addition of salt to the diet containing the lowest FM level on growth performances, feed conversion ratio, and intestinal solute carrier family 6 member 19 (SLC6A19) and oligopeptide transporter 1 (PEPT1) transcript levels, in freshwater-adapted European sea bass (Dicentrarchus labrax). We first isolated by molecular cloning and sequenced a full-length cDNA representing the neutral amino acid transporter SLC6A19 in sea bass. The cDNA sequence was deposited in GenBank database (accession no. KC812315). The twelve transmembrane domains and the 'de novo' prediction of the three-dimensional structure of SLC6A19 protein (634 amino acids) are presented. We then analysed diet-induced changes in the mRNA copies of SLC6A19 and PEPT1 genes in different portions of sea bass intestine using real-time RT-PCR. Sea bass were fed for 6 weeks on different diets, with ascending levels of fat or descending levels of FM, which was replaced with vegetable meal. The salt-enriched diet was prepared by adding 3 % NaCl to the diet containing 10 % FM. SLC6A19 mRNA in the anterior and posterior intestine of sea bass were not modulated by dietary protein sources and salt supplementation. Conversely, including salt in a diet containing a low FM percentage up-regulated the mRNA copies of PEPT1 in the hindgut. Fish growth correlated positively with the content of FM in the diets. Interestingly, the addition of salt to the diet containing 10 % FM improved feed intake, as well as specific growth rate and feed conversion ratio.