Fish silage prepared from different cooked and uncooked raw materials: chemical changes during storage at different temperatures

Four silage types were prepared from raw and cooked whole herring, whole mackerel, by‐products from the filleting‐line of cod and saithe, and from the viscera of cod. Each silage type was stored at 4, 20 and 50°C for 48 days. The raw materials were analysed fresh and after 2, 4, 8, 16, 32 and 48 days of storage. Dry matter, crude protein and total fat were not affected by the different storage temperatures or the length of the storage period. Neither was there any change in amino acid contents. Chemical composition in different silage types reflected the amounts in the raw materials used for silage production. Hydrolysis, on the other hand, varied with the type of raw material used for silage production as well as with the temperature under which the silages were stored. Cooked raw materials did not show any change in hydrolysis during storage. © 1999 Society of Chemical Industry     

Preparation, nutrient composition and digestibility of fermented shrimp head silage

Raw heads of the river prawn, Macrobrachium vollenhovenii, were fermented with Lactobacillus plantarum at 30 °C using molasses or cassava starch as the carbohydrate source. After incubation for 7 days, a desirable and stable pH < 4.5 was attained, and the carbohydrate source did not affect non-protein nitrogen (NPN) content or the proximate composition of the liquid silage after 30 days incubation. Hydrolysed feather meal, poultry by-product meal or soybean meal, used as alternative filler, was blended with the liquid silage (85:15, w/w) and solar-dried. The dried shrimp head silage meals were incorporated as protein supplements into pelleted semi-purified diets for catfish, Clarias gariepinus. Apparent digestibility coefficients of dry matter, crude protein, gross energy and essential amino acids in the silage by catfish fingerlings was high (> 70%). It was concluded that dried fermented fish silage is suitable and has a potential as a protein feedstuff in fish diets.     

Nutritive value of diets containing fish silage for juvenile Litopenaeus vannamei (Bonne, 1931)

BACKGROUND: Fish wastes has been used for many years as an alternative in feeds for aquaculture. In the present study weight gain of juvenile white shrimp Litopenaeus vannamei fed diets including fish waste silage (WS), fish waste silage with soybean meal SBM (WS + S) or fish waste meal (WM) was compared. A conventional acidic silage process was applied to obtain from wastes (skin, heads, bones and viscera) of snapper (Lutjanus spp.), grunt (Haemulon plumieri), and grouper (Epinephelus spp.) an ingredient rich in protein. RESULTS: After 3 days ensilage more than 90% protein was hydrolysed. Waste material processed at pH 3.8 lost about 24% tryptophan. Butylated hydroxytoluene (BHT) prevented lipid oxidation, as shown after 45 days with malonaldehyde production. Shrimp fed WS + S diet gained 0.7 g per week higher than those fed WS and WM diets with 0.3 g per week (P < 0.05). CONCLUSION: WS processed with formic acid under conditions of low pH is beneficial for the white shrimp L. vannamei. It sustained reasonable weight gain combined with soybean meal in practical diets. On the other hand, BHT addition was beneficial in preventing oxidative action during silage preparation. Copyright © 2012 Society of Chemical Industry     

Effect of re-ensiling on the quality of sorghum silage

The commercialization of silage in many countries, including Brazil, has increased in recent years. Re-ensiling of previously ensiled forage occurs when silage is relocated from one farm to another, where it will be compacted and sealed again. During this process, silage is exposed to oxygen before being ensiled, which may affect its quality. We exposed sorghum silage to air during the anaerobic storage phase to simulate the transportation of silages between farms. Experimental treatments included silage exposed to air for 0 or 12 h, with or without the use of an inoculant containing a mixture of Lactobacillus plantarum and the propionic bacteria Propionibacterium acidipropionici (1 × 10⁶ cfu/g of forage; Biomax corn, Lallemand, Saint-Simon, France), totaling 4 treatments: conventional silage, conventional silage with inoculant use, re-ensilage after exposure to air, and re-ensilage after exposure to air with use of an inoculant. The sorghum was stored in experimental silos containing about 9.0 kg of fresh forage per replicate. Treatments were tested in a factorial 2 × 2 design with 5 replicates each. Chemical composition, in vitro dry matter digestibility, fermentative characteristics, losses (due to gas, effluents, and total dry matter), microorganism counts, and aerobic stability of sorghum silage were evaluated. Dry matter content of sorghum before ensiling was 273.12 g/kg. The 12-h re-ensiling process increased the effluent loss of the silage when compared with conventional silage (456.42 vs. 201.19 g/kg of FM, respectively). In addition, re-ensiled silages presented lower concentrations of lactic acid and higher concentrations of propionic acid than the silages that had not been opened during storage. The aerobic stability of silage was not affected by the re-ensiling process and the use of inoculant. The use of inoculant increased the pH and loss of dry matter of the silages (4.23 vs. 3.98 and 14.05 vs. 7.82%, respectively) and therefore did not provide any benefits in this study.     

Production performance,nutrient digestibility,and milk fatty acid profile of lactating dairy cows fed corn silage- or sorghum silage-based diets with and without xylanase supplementation

The objective of this study was to evaluate the effects of supplementing xylanase on production performance, nutrient digestibility, and milk fatty acid profile in high-producing dairy cows consuming corn silage- or sorghum silage-based diets. Conventional corn (80,000 seeds/ha) and brown midrib forage sorghum (250,000 seeds/ha) were planted, harvested [34 and 32% of dry matter (DM), respectively], and ensiled for more than 10 mo. Four primiparous and 20 multiparous Holstein cows were randomly assigned to 1 of 4 diets in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments and 19-d periods. Treatment diets consisted of (1) corn silage-based diet without xylanase, (2) corn silage-based diet with xylanase, (3) sorghum silage-based diet without xylanase, and (4) sorghum silage-based diet with xylanase. The xylanase product was supplemented at a rate of 1.5 g of product/kg of total DM. Corn silage had higher concentrations of starch (31.2 vs. 29.2%), slightly higher concentrations of crude protein (7.1 vs. 6.8%) and fat (3.7 vs. 3.2%), and lower concentrations of neutral detergent fiber (36.4 vs. 49.0%) and lignin (2.1 vs. 5.7%) than sorghum silage. Xylanase supplementation did not affect DM intake, milk yield, milk fat percentage and yield, milk protein percentage and yield, lactose percentage and yield, and 3.5% fat-corrected milk yield. Cows consuming corn silage-based diets consumed 13% more DM (28.8 vs. 25.5 kg/d) and produced 5% more milk (51.6 vs. 48.9 kg/d) than cows consuming sorghum silage-based diets. Milk from cows consuming sorghum silage-based diets had 16% greater fat concentrations (3.84 and 3.30%) than milk from cows consuming corn silage-based diets. This resulted in 8% greater fat yields (1.81 vs. 1.68 kg/d). Silage type did not affect milk protein and lactose concentrations. Xylanase supplementation did not affect nutrient digestibility. Cows consuming corn silage-based diets showed greater DM (77.3 vs. 73.5%), crude protein (78.0 vs. 72.4), and starch (99.2 vs. 96.5%) digestibilities than cows consuming sorghum silage-based diets. In conclusion, xylanase supplementation did not improve production performance when high-producing dairy cows were fed corn silage- or sorghum silage-based diets. In addition, production performance can be sustained by feeding sorghum silage in replacement of corn silage.     

Comparison of brown midrib-6 and -18 forage sorghum with conventional sorghum and corn silage in diets of lactating dairy cows

Total mixed rations containing conventional forage sorghum, brown midrib (bmr)-6 forage sorghum, bmr-18 forage sorghum, or corn silage were fed to Holstein dairy cows to determine the effect on lactation, ruminal fermentation, and total tract nutrient digestion. Sixteen multiparous cows (4 ruminally fistulated; 124 d in milk) were assigned to 1 of 4 diets in a replicated Latin square design with 4-wk periods (21-d adaptation and 7 d of collection). Diets consisted of 40% test silage, 10% alfalfa silage, and 50% concentrate mix (dry basis). Acid detergent lignin concentration was reduced by 21 and 13%, respectively, for the bmr-6 and bmr-18 sorghum silages when compared with the conventional sorghum. Dry matter intake was not affected by diet. Production of 4% fat-corrected milk was greatest for cows fed bmr-6 (33.7 kg/d) and corn silage (33.3 kg/d), was least for cows fed the conventional sorghum (29.1 kg/d), and was intermediate for cows fed the bmr-18 sorghum (31.2 kg/d), which did not differ from any other diet. Total tract neutral detergent fiber (NDF) digestibility was greatest for the bmr-6 sorghum (54.4%) and corn silage (54.1%) diets and was lower for the conventional (40.8%) and bmr-18 sorghum (47.9%) diets. In situ extent of NDF digestion was greatest for the bmr-6 sorghum (76.4%) and corn silage (79.0%) diets, least for the conventional sorghum diet (70.4%), and intermediate for the bmr-18 sorghum silage diet (73.1%), which was not different from the other diets. Results of this study indicate that the bmr-6 sorghum hybrid outperformed the conventional sorghum hybrid; the bmr-18 sorghum was intermediate between conventional and bmr-6 in most cases. Additionally, the bmr-6 hybrid resulted in lactational performance equivalent to the corn hybrid used in this study. There are important compositional differences among bmr forage sorghum hybrids that need to be characterized to predict animal response accurately.     

Effect of low‐cost storage and packaging on quality and nutritive value of fresh and dehydrated carrots

Fresh carrots (Daucus carota L cv ‘Nantes’) were packed in Netlon and ventilated low‐density polyethylene bags and stored in ambient, cool chamber and cool store conditions. Blanching and drying conditions were standardised and the sliced carrots were dehydrated to 7–9% moisture content using the best blanching and drying combination. Dehydrated carrots were packed in single and double layers of high‐density polyethylene bags and stored in ambient and cool store conditions for 9 months. The shelf‐life of fresh carrots varied from 3 to 20 days depending on the packaging and storage condition. A reduction in β‐carotene and ascorbic acid content and an increase in electrolyte leakage were observed during storage of fresh carrots. Blanching and drying caused a significant reduction in β‐carotene and ascorbic acid content, which further decreased during storage of dried product. The storage study of dried product showed that retention of β‐carotene and ascorbic acid was better in double‐packed and cool‐stored samples, and it also showed minimum browning during storage. © 2000 Society of Chemical Industry     

Effect of replacing alfalfa silage with high moisture corn on ruminal protein synthesis estimated from excretion of total purine derivatives

Twenty-four multiparous dairy cows (eight with ruminal cannulae) were blocked by days in milk and assigned to six balanced 4 x 4 Latin squares with 21-d periods. The four diets, formulated from alfalfa silage plus a concentrate mix based on ground high moisture ear corn, contained (dry matter basis): 1) 20% concentrate, 80% alfalfa silage (24% nonfiber carbohydrate; NFC), 2) 35% concentrate, 65% alfalfa silage (30% NFC), 3) 50% concentrate, 50% alfalfa silage (37% NFC), or 4) 65% concentrate, 35% alfalfa silage (43% NFC). Soybean meal and urea were added to make diets isonitrogenous with equal nonprotein nitrogen (NPN) (43% of total N). Total urine was collected with indwelling Folley catheters for 24 h during each period. There was no effect of diet on urinary creatinine excretion (average 29 mg/kg of BW/d). There were quadratic effects of diet on total urinary ecretion of allantoin, uric acid, and purine derivatives (allantoin plus uric acid), and on ruminal synthesis of microbial N estimated from purine derivatives; maxima occurred at about 35% dietary NFC. Urinary excretion also was estimated with spot urine samples from creatinine concentration and the mean daily creatinine excretion. Daily excretion of allantoin, uric acid, and purine derivatives estimated from spot urine sampling followed the same pattern as that observed with total collection; differences between measured and estimated urine volume were significant only for 35% dietary concentrate. Spot urine sampling appeared to yield satisfactory estimates of purine derivative excretion. Maximal urea N excretion was estimated to occur at about 31% dietary NFC. Milk allantoin secretion increased linearly with concentrate and accounted for 4 to 6% of the total purine derivative excretion. Microbial yield was maximal at 35% dietary NFC, suggesting that this was the optimal level for utilization of dietary NPN from alfalfa silage and other sources.     

Effect of reconstitution of sorghum with or without enzymes on production performance and immunocompetence in broiler chicken

BACKGROUND: The presence of tannins and phytic acid in sorghum causes anti‐nutritional effects that include reduced growth rate, feed intake, feed efficiency and nutrient digestibility in broiler chicken. Therefore, in the present investigation efforts were made to reveal the effect of reconstitution of sorghum with or without enzymes on production performance and immunocompetence in broiler chicken. RESULTS: The body weight gain, feed conversion ratio, energy and protein utilization efficiency were better in birds fed reconstituted sorghum in comparison to those fed untreated sorghum. The intake of feed in different treatments did not vary in comparison to the control group. The feed cost per unit weight gain or meat yield apparently reduced due to reconstitution. There was significant improvement in nitrogen corrected apparent metabolizable energy (AMEn) of diets containing reconstituted sorghum. The serum biochemical parameters such as total cholesterol, triglycerides and uric acid were not affected due to dietary treatments. The cell‐mediated immune response to phytohaemagglutinin‐P was better in sorghum‐fed groups. However, the humoral response to sheep red blood cells remained unaffected owing to the substitution of the maize by sorghum or its processed form. CONCLUSION: The results suggest that the reconstitution of sorghum was beneficial in improving the growth performance and nutrient utilization in broiler chicken. However, supplementation of enzymes to raw sorghum‐based diets or addition of enzymes during reconstitution of sorghum did not further improve the growth performance of broilers. Copyright © 2009 Society of Chemical Industry     

Nutritional value of fish viscera silage

Fish viscera silage has been prepared from cod (Gadus morhua) and saithe (Pollachius virens) by mincing the viscera and adding a mixture of formic and propionic acids [1:1 (w/v)] to a final concentration of 1.5% (w/v). Feeding experiments were performed with rats using: (a) freshly prepared silage; (b) fish viscera silage stored for up to 4 days at 30°C; and (c) de-oiled silage prepared after autolysis and subsequent storage for up to 60 days at 15°C. The nutritional value of the silage has been improved by storage and lipid removal, giving an increase of net protein utilisation (NPU) from below 60% for freshly prepared silage to 70% or above after lipid removal. This increase of NPU can be attributed mainly to an increase in the level of lysine.     

Feeding Lactating Dairy Cows Proteins Resistant to Ruminal Degradation

Sixty multiprious Holstein cows were fed treatment diets from 11 to 40 d postpartum with corn silage as the forage. Treatment diets each contained a different supplemental protein: 1) solvent soybean meal; 2) extruded soy product; 3) combination of corn gluten meal and distillers dried grains with solubles; and 4) a combination of protein sources from diets 2 and 3. Covariate adjusted means for milk (kg/d) and milk fat (%) for treatments 1 through 4 were 37.5, 3.14; 38.5, 3.19; 31.8, 3.45; and 35.2, 3.08. Milk protein content and DM intake were greatest for cows fed diet 1.In a second trial, 105 multiparous Holstein cows 13 d postpartum were placed on 7 treatment diets for 60 d. Treatments 1 to 5 contained equal amounts of corn silage and alfalfa silage as forage sources and contained either: 1) solvent soybean meal; 2) roasted soybean meal; 3) roasted soybeans; 4) roasted soybeans and urea; or 5) a mixture of corn distillers dried grains and corn gluten meal. Treatments 6 and 7 had alfalfa silage as the forage source and either 6) solvent soybean meal or 7) roasted soybeans as the supplemental protein. Feeding roasted soybeans with the alfalfa silage-based diets increased milk 2.0 kg/d, 4% FCM 4.6 kg/d, and fat .23 kg/d when compared with solvent soybean meal. Milk protein production was depressed by feeding a combination of distillers dried grains and corn gluten meal when compared with feeding diets containing soybean sources with the corn silage-alfalfa silage diets. Resistant protein sources may have greater value with diets containing alfalfa silage than with diets containing corn silage.     

Chemical,microbiological and sensory changes of dried Acetes chinensis during accelerated storage

Chemical, microbiological and sensory changes of dried Acetes chinensis during 28 days of accelerated storage at 37 °C were studied. Eighty volatile components including alcohols, aldehydes, acids, ketones, esters, alkanes, nitrogen-containing components, aromatic components and terpenes were identified by headspace sampling and gas chromatography–mass spectrometry (GC–MS) method during storage. Among these volatile components, the relative content of trimethylamine was the highest during storage, which increased from 11.36 ± 1.02% at day 0 to 14.60 ± 0.58% at day 28. Values of total volatile base nitrogen (TVB-N), trimethylamine (TMA), thiobarturic acid reactive substances (TBARS), total viable mesophilic count (TVC) and sensory characteristics of colour and odour for dried A. chinensis changed significantly during storage. Volatile components, TVB-N, TMA, pH, TBARS, TVC, colour and odour characteristics at different storage time were statistically interpreted by principle component analysis (PCA) method in order to found the main indices for the freshness of dried A. chinensis. The results suggested that colour, TMA, TVB-N, TBARS, odour, TVC and some volatile components could reflect the quality changes perfectly.     

Changes during ensilage in fermentation products,tea catechins,antioxidative activity and in vitro gas production of green tea waste stored with or without dried beet pulp

Wet green tea waste (GTW) was ensiled in laboratory silos with or without dried beet pulp at a ratio of 2:1 on a fresh weight basis. The silos were opened at 15, 30 and 60 days after anaerobic storage; fermentation products, tea catechins, antioxidative activity and in vitro gas production were determined. Acetic acid prevailed over the fermentation and the pH declined to below 4.2 when wet GTW was ensiled alone. Addition of dried beet pulp greatly enhanced lactic acid production and the pH further decreased to below 3.8 with no butyric acid being detected. Approximately 90% and 80% of (?)‐epicatechin gallate and (?)‐epigallocatechin gallate, respectively, were degraded in silage prepared from wet GTW alone, while the degradation was ameliorated in mixed silage to about 55% and 70%, respectively. Antioxidative activity was not markedly altered by ensiling and 70–80% of the initial activity was detected after 60 days. Changes were small in (?)‐epigallocatechin, caffeine and total phenols with or without mixing with dried beet pulp. In vitro gas production was similar between materials and their silages, indicating that reduction of tea catechins would not elicit an improvement in digestibility. It is concluded that wet GTW can be ensiled successfully without bacterial inoculants when mixed with other materials containing certain sugars. Ensiling may degrade part of the components of tea catechins, while not affecting total phenols, antioxidative activity and digestibility of wet GTW. Copyright © 2007 Society of Chemical Industry     

Sensory quality of marinated frozen stored chicken thighs as affected by dietary fish fat and vitamin E

The effects of diets containing fish meal (0 or 4%), fish silage (0 or 4%) and vitamin E (60 or 200 mg kg^–1) and the processing effect of marinating with sodium citrate (0.24 or 0.48%) or ascorbate (0.31 or 0.62%) have been studied to test the hypothesis that oxidative stability of frozen stored chicken thighs can be improved by such treatments. A trained sensory panel assessed the samples after storage at –25 °C for 1 week, 3 and 6 months. Feed with 4% fish meal resulted in increased fish flavour and odour of the thighs while 4% fish silage had a smaller effect on these attributes. Fish meal and fish silage added together into the feed by an amount of 4% each, caused strong fish flavour and odour in the product and accelerated the rancidity process. High concentration of vitamin E (200 mg kg^–1) in the feed reduced rancidity when 4% fish products had been added to the feed, but no effect was noted when 4% fish meal plus 4% fish silage had been added together. High concentration of ascorbate in the brine (0.62%) decreased sensory score for rancidity attributes (hay, grass, soap and paint), while high concentration of citrate (0.48%) increased these parameters in frozen stored chicken thighs.     

Silage from tropical fish 3. Lipid behaviour

Acid silages were prepared from silverbelly ( Leiognathus spp.) at 30°C with 3% (w/w) of 98% formic acid. Lipid oxidation takes place actively during ensilation as demonstrated by changes in fatty acid composition, TBA value and peroxide value. Lipid extraction, with chloroform: methanol or isopropanol, or the addition of an antioxidant before ensilation can limit the build up of lipid oxidation products. Lipid extraction also suppresses the autolysis of proteins in a defatted silage compared with a normal silage when measured by total soluble nitrogen or soluble NPN. The solubilization of collagen appears to be unaffected by lipid extraction perhaps reflecting the non-enzymic nature of this process. The limited autolysis in defatted silages may be beneficial in restricting the release of free amino acids capable of reacting with lipid oxidation products resulting in a lower nutritional value for silage based diets.     

Efficacy of carbohydrate sources for milk production by cows fed diets based on alfalfa silage

The effectiveness of three carbohydrate sources, high-moisture ear corn (HMEC), cracked shelled corn (CSC), and a 50:50 mixture of HMEC plus dried citrus pulp (DCP), fed with or without supplemental rumen-undegraded protein as expeller soybean meal (ESBM), was assessed in 48 multiparous dairy cows. All diets contained (dry mater [DM] basis) 50% alfalfa silage, 10% ryegrass silage, 28% NDF, and one of six concentrates: A) 38% HMEC; B) 38% CSC; C) 19% DCP plus 19% HMEC; D) 27% HMEC plus 12% ESBM; E) 27% CSC plus 12% ESBM; or F) 13% DCP, 13% HMEC, and 12% ESBM. Diets A, B, and C averaged 19% crude protein, of which 53% was nonprotein nitrogen (NPN), and diets D, E, and F averaged 22% crude protein, of which 40% was NPN. Cows were fed a high-energy covariate diet for 2 wk, blocked into eight groups of six, based on covariate protein yield, then randomly assigned to diets that were fed for 12 wk. Feeding ESBM increased DM intake, yields of milk, fat-corrected milk, fat, protein, SNF, and milk and blood urea concentration and decreased weight loss. There were no production differences between HMEC and CSC. However, DM intake, yields of milk, fat-corrected milk, fat, protein, lactose, SNF, and milk SNF content all were lower on the diets containing DCP versus HMEC and CSC. A 6 x 6 Latin square trial conducted at the same time with six ruminally cannulated cows showed similar effects of diet on DM intake and milk production. Ruminal ammonia was elevated by ESBM but not ruminal total amino acids and branched-chain volatile fatty acids. Ruminal propionate was highest on HMEC diets and lowest on DCP diets; acetate, butyrate and acetate-to-propionate ratio were lowest on HMEC diets and highest on DCP diets. These results indicated that, compared to HMEC and CSC, feeding the pectin-rich carbohydrate source DCP altered ruminal fermentation but depressed intake and milk production in lactating cows.     

In vitro starch digestibility of fresh and sun‐dried faba beans (Vicia faba L.)

Fresh and sun‐dried faba beans (Vicia faba L.) were cooked, stored for various times at 4 °C and analysed for available starch (AS), resistant starch (RS) and fibre‐associated resistant starch (FARS) contents as well as α‐amylolysis. Fresh beans required a shorter cooking time (25 min) than dried beans (158 min). Cooked fresh faba beans had a higher AS content than cooked dried faba beans. The AS content in both decreased during cold storage, with fresh beans showing a smaller decrease than dried beans with increasing storage time. Cooked fresh faba beans also had a higher total RS content than cooked dried faba beans, although a greater increase in RS content was recorded in the latter upon storage. Starch retrogradation was more prominent in cooked dried faba beans than in cooked fresh faba beans, as indicated by the consistently higher FARS content. The α‐amylolysis rate decreased with increasing storage time, i.e. long‐stored (72 h) cooked faba beans exhibited slower starch digestion, and differences were recorded between fresh and dried beans. The predicted glycaemic index ranged between 60.9 and 58.0% for cooked fresh faba beans and between 57.9 and 55.8% for cooked dried faba beans, which is suggestive of slow glucose release from starch in faba beans. Copyright © 2007 Society of Chemical Industry     

Effects of feeding formate-treated alfalfa silage or red clover silage on omasal nutrient flow and microbial protein synthesis in lactating dairy cows

Eight ruminally cannulated Holstein cows that were part of a larger lactation trial were blocked by days in milk and randomly assigned to replicated 4 × 4 Latin squares to quantify effects of nonprotein N (NPN) content of alfalfa silage (AS) and red clover silage (RCS) on omasal nutrient flows. Diets, fed as total mixed rations, contained 50% dry matter from control AS (CAS), ammonium tetraformate-treated AS (TAS), late maturity RCS (RCS1), or early maturity RCS (RCS2). Silages differed in NPN and acid detergent insoluble N (% of total N): 50 and 4% (CAS); 45 and 3% (TAS); 27 and 8% (RCS1); 29 and 4% (RCS2). The CAS, TAS, and RCS2 diets had 36% high-moisture shelled corn and 3% soybean meal, and the RCS1 diet had 31% high-moisture shelled corn and 9% soybean meal. All diets contained 10% corn silage, 27% neutral detergent fiber, and 17 to 18% crude protein. Compared with RCS, feeding AS increased the supply of rumen-degraded protein and omasal flows of nonammonia N and microbial protein, which may explain the improved milk yield observed in the companion lactation trial. However, omasal flow of rumen-undegraded protein was 34% greater on RCS. Except for Arg, omasal flows of individual AA, branched-chain AA, nonessential AA, essential AA, and total AA did not differ between cows fed AS vs. RCS. Within AS diets, no differences in omasal AA flows were observed. However, omasal flows of Asp, Ser, Glu, Cys, Val, Ile, Tyr, Lys, total nonessential AA, and total AA all were higher in cows fed RCS1 vs. cows fed RCS2. In this trial, there was no advantage to reducing NPN content of hay-crop silage.     

Storage Quality of Fresh and Frozen-thawed Fish in Ice

The objective was to determine whether traditional quality indexes of fresh (unfrozen) fish like sensory analysis, bacterial counts and trimethylamine content could be applied to thawed whole cod, cod fillets and ocean perch fillets kept in ice. Freezing and short-term freezer storage (≤5 wk at ?25°C) had very little effect on bacterial counts. During long-term freezer storage (≥14 wk at ?25°C) total counts were reduced as well as counts of trimethylamine oxide-reducing bacteria in cod fillets but not in ocean perch fillets. When the thawed fish was unacceptable the trimethylamine was <1 mgN/100g. Trimethylamine as a spoilage indicator was of no value when evaluating spoilage of thawed whole cod, cod fillets and ocean perch fillets kept in ice.     

不同前期储藏条件对鲢鱼烹饪特性的影响

研究了不同的前期储藏处理对鲢鱼烹制品质的作用。鲢鱼块在冷藏(-1℃)和冻藏(-20℃)条件下储藏0、3、6、9、12d后进行烹制处理,从化学、物理及感官方面评价储藏温度及时间对烹制后鲢鱼品质的影响。试验结果表明,烹制处理提高了鲢鱼肉的NPN、TVB-N及TMA含量;随储藏时间的延长,冷藏和冻藏的鲢鱼经烹制处理后鱼肉中总氮含量呈逐渐降低趋势,而非蛋白氮(NPN)、挥发性盐基氮(TVB-N)和三甲胺(TMA)含量均呈逐渐增加趋势,冷藏比冻藏的变化趋势显著。储藏时间越长,烹制后鱼肉组织质量劣化越严重。冷藏条件下适宜储藏时间不超过9d,也可延长至12d,且前期冻藏有利于保证鲢鱼肉烹制后的品质。