Anders Skrede

Apparent digestibility of protein, amino acids and energy in rainbow trout (Oncorhynchus mykiss) fed a fish meal based diet extruded at different temperatures

A fish meal/wheat flour based dry ingredient mix was extruded at three different temperatures (100, 125 and 150 °C), by varying extrusion conditions according to two different methods. Employing method 1, the temperature of the conditioner, torque, screw speed, pressure, feed rate and process water of the extruder were varied. Whereas in method 2, conditioner temperature and screw speed were kept constant, and the variation in process water input was restricted. The diets, which contained yttrium oxide as an inert maker, were fed to three replicate groups of rainbow trout. Feces for digestibility determination were obtained by stripping. The results showed that the differences in extrusion temperature caused no significant differences in apparent digestibilities of crude protein, individual amino acids or energy. The apparent digestibility of cysteine was significantly higher for diets produced by method 1 than by method 2.

Digestibility of fat and fatty acids in rainbow trout and mink

The digestibility of different fats in rainbow trout and mink showed somewhat higher values in mink than in fish. Digestibility coefficients in fish did not exhibit distinct differences between two water temperatures (3 and 11°C). Rainbow trout and mink responded very similarly to digestibility differences between dietary fats and fatty acids. Both species revealed decreasing digestibility of total lipids and fatty acids with increasing melting point. Thus soybean oil, cod liver oil and capelin oil were efficiently digested, while hydrogenation of capelin oil resulted in decreased digestibility. Mild hydrogenation to 21°C melting point had a slight effect. The digestibility of saturated and unsaturated fatty acids were similarly influenced by hydrogenation. The digestibility of individual fatty acids decreased with increasing chain length up to C18. A further increase in chain length up to C22 caused increased digestibility. Unsaturated acids showed higher digestibility than their saturated counterparts.

Effect of heat treatment of soybean meal and fish meal on amino acid digestibility in mink and dairy cows

Commercial solvent extracted soybean meal (SBM) and fish meal (FM) subjected to additional moist heat for 30 min at 120 or 130°C were investigated in terms of amino acid (AA) composition, total tract digestibility in mink, rumen and total tract digestibility in dairy cows of crude protein (CP) and individual AA. Heat treatment of SBM at 130°C caused significant reduction of the content of Arg, Lys and Cys by 4.1, 8.2 and 12.5%, respectively. Digestibility in mink of CP and most AA was significantly reduced after heat treatment of SBM at 120°C and further at 130°C. The digestibilities of Cys, Asp and Lys, which were the most severely affected AA, declined with 12.3, 10.9 and 8.8 percentage units, respectively, after treatment at 130°C. Heat treatment of FM at 120°C caused reduced digestibility of CP and His, Ile, Lys, Met, Asp, Glu, Gly, and Ser, while heat treatment at 130°C reduced total tract digestibility of CP and all AA in mink. Digestibility of Asp and Cys were most affected after heat treatment at 130°C with reduction of 17.9 and 11.4 percentage units, respectively. Rumen degradability of CP and all AA was significantly lowered by heat treatment of SBM. Met and Glu were the most affected AA, with a reduction of degradability after 16 h rumen incubation of 62.1 and 58.0 percentage units, respectively, after treatment at 130°C. Heat treatment of FM at 120°C caused declined rumen degradability of CP and total AA, although not to the same extent as for SBM. There was no additional effect on rumen degradability of treatment at 130°C of FM. Rumen degradation of Glu and His, the most affected AA, in FM was reduced with 25.1 and 20.3 percentage units, respectively, following heat treatment at 120°C. Ruminant total tract digestibility of CP and AA was not significantly affected by treatment for either of the protein sources. Additional heat treatment of SBM reduced the rumen degradability of protein and AA more than treatment of FM, while for the nonruminant mink, total tract digestibility of SBM and FM was reduced similarly following heat treatment.

Lactic acid fermentation of wheat and barley whole meal flours improves digestibility of nutrients and energy in Atlantic salmon (Salmo salar L.) diets

The effects of lactic acid fermentation of wheat and barley whole meal flours (WMF) on digestibility parameters in Atlantic salmon were studied. The WMFs were inoculated with a specific Lactobacillus strain and fermented for 16 h at 30 °C prior to mixing with other feed ingredients and processing by extrusion. Fermentation of the WMFs significantly decreased total starch (P<0.01) and total mixed-linked (1–3)(1–4)-β-glucan (P<0.001) contents in both cereals. Soluble β-glucans decreased (P<0.001) from 25.2 to 12.0 g kg−1 dry matter in barley WMF during fermentation. In Experiment 1, where diets with 24% untreated wheat or barley WMF and 12%, 24%, or 36% fermented WMFs were fed to Atlantic salmon (0.5 kg) for 25 days, there were indications of improved starch and fat digestibility by fermentation. Experiment 2 comprised diets containing 24% untreated or fermented wheat or barley WMFs fed to each of triplicate groups of Atlantic salmon (0.5 kg) during a 17-day experimental period. This experiment showed that protein (P<0.001), fat (P<0.05) and energy (P<0.001) were more efficiently digested in diets with wheat than in diets with barley. Apparent digestibility of starch was greatly improved by fermentation (P<0.001), more in barley diets (from 47.5% to 67.0%) than in wheat diets (from 51.7% to 65.4%). Improvements in digestibility of fat (P<0.05) and energy (P<0.001) were obtained by fermenting the cereals. The absorption of Na was higher for salmon fed wheat than barley diets (P<0.05). Fermentation resulted in improved Na absorption (P<0.01); from 68.8% to 73.2% for wheat diets and from 60.3% to 71.7% for barley diets. Fermentation caused a significant (P<0.05) improvement in Zn absorption from 32.7% to 40.5% for wheat diets and from 33.2% to 43.5% for barley diets. This may be related to the significant reduction in phytic acid levels seen in both fermented cereals (P<0.001). In conclusion, the potential of wheat and especially barley as ingredients in salmon diets is greatly improved by fermentation.

Evaluation of methane-utilising bacteria products as feed ingredients for monogastric animals

Bacterial proteins represent a potential future nutrient source for monogastric animal production because they can be grown rapidly on substrates with minimum dependence on soil, water, and climate conditions. This review summarises the current knowledge on methane-utilising bacteria as feed ingredients for animals. We present results from earlier work and recent findings concerning bacterial protein, including the production process, chemical composition, effects on nutrient digestibility, metabolism, and growth performance in several monogastric species, including pigs, broiler chickens, mink (Mustela vison), fox (Alopex lagopus), Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), and Atlantic halibut (Hippoglossus hippoglossus). It is concluded that bacterial meal (BM) derived from natural gas fermentation, utilising a bacteria culture containing mainly the methanotroph Methylococcus capsulatus (Bath), is a promising source of protein based on criteria such as amino acid composition, digestibility, and animal performance and health. Future research challenges include modified downstream processing to produce value-added products, and improved understanding of factors contributing to nutrient availability and animal performance.

Bacteria Grown on Natural Gas Prevent Soybean Meal-Induced Enteritis in Atlantic Salmon

Dietary inclusion of solvent extracted soybean meal (SBM) is associated with inflammation in the distal intestine of salmonid fish, commonly referred to as SBM-induced enteritis. The enteritis is linked to alcohol soluble components in SBM, but the mechanisms have not been established. Previous studies show that bacterial meal (BM) containing mainly Methylococcus capsulatus grown on natural gas is a suitable protein source for salmonids. The BM is rich in nucleotides, phospholipids, and small peptides that might be beneficial for intestinal homeostasis. In this study, a fish meal (FM)-based control diet (FM diet) and diets with 200 g/kg SBM (SBM diet), 300 g/kg BM (BM diet), and 300 g/kg BM and 200 g/kg SBM (BM-SBM diet) were fed to juvenile Atlantic salmon (Salmo salar) for 80 d. Dietary inclusion of SBM reduced growth (P = 0.007). Inclusion of BM reduced digestibility of protein (P = 0.002) and lipids (P = 0.011) and increased (P < 0.01) the relative weights (g/kg whole body) of total gut, liver, and stomach, and mid and distal intestine. Fish fed the SBM diet developed enteritis, lacked carbonic anhydrase 12 in the brush border of epithelial cells in distal intestine, and had more epithelial cells reacting for proliferating cell nuclear antigen compared with fish fed the other diets. Fish fed the same amount of SBM combined with BM showed no signs of inflammation in the distal intestine. Our results demonstrate that BM grown on natural gas can be used to prevent SBM-induced enteritis in Atlantic salmon.

Effect of extrusion on trypsin inhibitor activity and nutrient digestibility of diets based on fish meal, soybean meal and white flakes

Abstract The effects of moist extrusion processing of diets containing fish meal (FM) and conventional defatted soybean meal (SBM) or untoasted defatted soybean meal (white flakes [WF]) on amino acid composition, trypsin inhibitor activity (TIA), and apparent total tract digestibility of nutrients were studied. Three diets with the nutritional characteristics of feeds for salmonid fish were formulated: one control based on FM as protein source and two others where 40% of total amino acids from FM were substituted by either SBM or WF. Each diet was fed to mink either as an unextruded mixture of the ingredients or as extruded pellets in order to determine the effect of extrusion processing. Extrusion did not change the amino acid composition of the diets significantly, but reduced the TIA of both diets containing soy products by approximately 76%. Intake of the unextruded WF diet was only one-third compared with the other diets. The dry matter concentration in faeces from mink fed diets containing soy products was significantly lower than in mink fed the FM diet. Digestibility of crude protein, all amino acids and fat was lower, but starch higher, in the unextruded WF diet than in the FM and SBM diets, whereas no significant differences were found among the extruded diets. Extrusion of the WF diet increased digestibility of protein and all amino acids. The greatest increase in digestibility after extrusion of the WF diet was observed for cysteine followed by tryptophan. Extrusion of the FM and SBM diets had no significant effect on amino acid digestibility. Digestibility of starch was, in general, increased by extrusion. It is concluded that the heat treatment involved in typical moist extrusion processing used for fish feed may be sufficient to inactivate most of the TIA in unheated soybean meal, and to increase digestibility of the protein in WF to approximately the same level as found for SBM and FM. Still, extrusion is a lenient process with minor effects on nutrient digestibility of diets containing fish meal or toasted soybean meal as major protein sources.

Effects of lactic acid fermentation on wheat and barley carbohydrate composition and production performance in the chicken

Effects of dietary inclusion of dried lactic acid fermented wheat or barley whole meal flours (WMF) on chicken performance were studied. WMFs were fermented for 16 h at 30 ◦ Cb y aLactobacillus strain isolated from a Norwegian rye sourdough. Four diets containing 600 g wheat WMF kg −1 (0, 200, 400 and 600 g fermented kg −1 ) and three diets containing 600 g barley WMF kg −1 (0, 400 and 600 g fermented kg −1 ) were used. Each treatment comprised 125 one-day-old sexed chickens (Ross) were fed on experimental diets until slaughtering at 35 days. Average weight, feed intake and feed:gain ratio in the 0–14, 14–35 and 0–35-day periods were recorded. At day 35, six chickens of each sex from each diet were slaughtered for determination of dressing percentage and abdominal fat. Fermentation significantly reduced levels of total and soluble dietary fibre in cereal WMF. In barley WMF, total-glucans decreased from 36.9 to 29.3 g kg −1 dry matter (DM) and soluble -glucans from 17.8 to 12.6 g kg −1 DM after fermentation. The effects of fermentation on dietary fibre and -glucans were reflected in the analysis of the experimental diets. Total starch was not significantly affected by fermentation. Cereal source and level of fermented WMF in the diets significantly affected chicken body weights. At 14 days, average weights were increased from 277 to 333 g for wheat diets, and from 252 to 322 g for barley diets, when untreated WMF was entirely substituted by fermented WMF. Linear regressions showed significant increase in average weight at 14 days with increasing levels of fermented wheat (R 2 = 0.448 ∗∗∗ ) and fermented barley (R 2 = 0.604 ∗∗∗ ). The effects of fermentation on weights at 14 days were similar for wheat and barley, as there was no significant difference between the regression slopes. Feed intake during the 0–14-day period was not significantly affected by the content of fermented cereal in the diet. Increasing level of fermented cereal significantly improved feed:gain ratio during the 0–14-day period for both

Bacterial Protein Grown on Natural Gas as Feed for Pigs

Bacterial protein meal (BPM) produced by a mixture of Methylococcus capsulatus (Bath), Alcaligenes acidovorans, Bacillus brevis and Bacillus firmus grown on natural gas, was studied as a protein source for pigs. Three growth trials were conducted, one with weanling pigs (Expt 1) and two with growing-finishing pigs (Expts 2 and 3). In Expt 1, 64 appetitefed weanling pigs (10.4 kg average initial weight) were used to determine the effect of adding BPM (0 g, 40 g, 80 g and 120 g kg-1) to diets replacing traditional protein feedstuffs on growth performance. During week 0-2, adding BPM to diets increased average daily gain (ADG) (linear P < 0.03). During week 0-2 and week 0-4, the 120 g kg-1 BPM diet increased (P < 0.01) average daily feed intake compared with the control and the 50 g kg-1

Effects of dietary fish silage and fish fat on growth performance and sensory quality of growing-finishing pigs

Thirty-six growing-finishing pigs, with an average initial weight of 24.8 kg ± 2.6 SD, were allocated to six groups to determine the effect of fish silage and fish fat in the diet on performance, carcass characteristics and sensory quality. The treatments were either a control diet, or one of three diets containing 50 g kg−1 fish silage and different levels of fish fat (2.5, 5.5 or 9.5 g kg−1). The diets were either fed until the time of slaughter (treatments CO, FSA1, FSB1 and FSC1), or until 60 kg liveweight followed by the control diet (the diets with 5.5 [treatment FSB2] and 9.5 g kg−1 fish fat [treatment FSC2]). Pigs were slaughtered at 98.7 kg ± 4.5 SD. No significant differences in growth performance or carcass quality were found among diets. The contents of the fatty acids C20:1 and C22:6 in the subcutaneous fat was increased by the dietary inclusion of fish silage. The total level of omega-3 fatty acids were highest for the 9.5 and the 5.5 g kg−1 fish fat diets when they were fed until slaughter....