Fish Meal Supplementation Research Articles

The catalytic effect of supplementation of protein meals on utilization of rice straw-poultry droppings-rice bran diet in buffaloes

Four graded Murrah ( Bubalus bubalis) bull calves (198.5 ± 3.0 kg) fitted with permanent rumen cannulae were used in a 4 × 4 latin square design to study the effect of supplementation of protein meals viz., groundnut cake (D-2), soyabean meal (D-3) or fish meal (D-4) at 100 g each to caged poultry droppings (CPD)-molasses-deoiled rice bran (DORB)-mineral (1810 g) mixture (D-1) and ad lib rice straw on in sacco rumen degradability of rice straw, voluntary feed intake, nutrient utilization and rumen fermentation pattern. Rumen degradation characteristics of dry matter (DM) and neutral detergent fibre (NDF) of rice straw (RS) and DM and crude protein (CP) of protein meals were described by fitting the in sacco data to the exponential equation p = a + b(1 − e − ct ). Rumen environment created by groundnut cake (GNC), soyabean meal (SBM) and fish meal (FM) supplementation increased ( P < 0.10) the rate of DM degradability ( c) of straw by 23.4%, 27.6% and 15.8%, respectively. Effective protein degradability of protein meals revealed that GNC protein was highly rumen degradable (93.2%) while FM protein was less degradable (49.2%) with SBM protein being intermediate (82.1%). Rates of protein degradability of GNC, SBM and FM were 0.1927, 0.2399 and 0.0720, respectively. Protein meal supplementation non-significantly increased rice straw and total DM intake (DMI) and significantly increased the DMI as a percentage of body weight ( P < 0.05) and per kilogram of metabolic body size ( P < 0.10). Voluntary DMI of buffaloes per kilogram W 0.75 was 81.9, 88.9, 89.6 and 91.0 g for D-1, D-2, D-3 and D-4, respectively. The apparent digestibilities of DM, OM, CP, NDF, acid detergent fibre (ADF) and cellulose were increased ( P < 0.01) due to supplementation of protein meal. It further increased the consumption of digestible crude protein (DCP) ( P < 0.01), metabolizable energy (ME) and DOM ( P < 0.05) and N retention ( P < 0.01) of buffaloes kept on RS diet. Animals fed FM diet had lower urinary N excretion and higher ( P < 0.01) N retention. Rumen NH 3-N concentration was significantly lower ( P < 0.01) in animals fed D-4 while animals fed D-3 or D-4 had significantly higher ( P < 0.01) total volatile fatty acid (TVFA) concentration. It is concluded that supplementation of RS-CPD based diet with various protein meals improved the performance of buffaloes with FM protein being superior in comparison with protein from GNC or SBM.

Response of growing steers to diets containing big bale silage and supplements of molassed sugar beet pulp with and without white fish meal

Twenty four steers, either Limousin ♂ or Simmental ♂ × (British Hereford ♂ × Friesian ♀) ♀ genotype were used in a 77 day study. Initial mean live weights were 288 kg and the steers were allocated by randomised block design to one of four treatments. The treatments were big bale silage fed alone ad libitum (C) or supplemented (kg dry matter (DM) day −1) with molassed sugar beet pulp (MSBP) 0.66 (S), 0.66 MSBP + 0.12 white fishmeal (FM) (SF1) or 0.66 MSBP + 0.23 FM (SF2). The silage (292 g DM kg −1) was of moderate fermentation quality and contained an estimated 9.7 MJ Metabolisable Energy and 93 g crude protein kg −1 DM. Supplementation with MSBP alone or together with FM significantly reduced silage DM intake although there was evidence of a reduction in the magnitude of this effect due to FM supplementation. MSBP supplementation alone did not increase live-weight gain but supplementation with FM significantly increased live-weight gain with no significant differences observed between diets SF1 and SF2. Food conversion ratio was non-significantly improved by MSBP alone, with further significant improvements due to FM. None of the supplementary treatments significantly improved apparent digestibility of organic matter or nitrogen (N). N intake was significantly elevated by FM supplementation which was associated with trends towards a greater N retention and significant increases in rumen ammonia and volatile fatty acid (VFA) and blood plasma urea concentrations. Molar proportions of rumen VFA were not altered by treatment. There was a trend towards an improvement in rumen microbial protein synthesis estimated by purine derivative excretion only on Diet SF2. This result coupled with the trends towards increases in silage intake may suggest some improvement in digestive activity. In addition a major anabolic effect of FM supplementation of the diets may have occurred post-absorptively and may relate to the supply of, for example, essential amino acids. The results indicated that moderate growth performance (0.6 kg day −1 LWG) can be achieved with diets based on big bale silage with low crude protein concentrations of 95–100 g kg −1 DM which were improved by supplementation of MSBP with FM. The interaction between big bale silage and MSBP and N sources and levels needs further investigation.

Effect of fish meal on digestibility in the rumen

Some studies have shown that fish meal (FM) supplementation could result in an increased digestion in the rumen, with different levels of response with different FM (McAllan, 1991). The aim of the experiment was to study the effects of supplementation with two FM, having the same nitrogen content (113 g N/kg DM) but different N rumen degradability, on fermentation and duodenal flow of nutrients.The study was carried out using six mature sheep fitted with rumen cannulae and single duodenal cannulae. Animals were fed 1 kg/d of a 60:40 hay:concentrate diet having a N content of 22 g/kg DM, either alone (Control; C) or supplemented with 40 g FM/d (FMl and FM2). The experiment was carried out over four periods of 14 days and in each period two sheep received each of the diets.

Effect of fish meal on digestibility in the rumen

Some studies have shown that fish meal (FM) supplementation could result in an increased digestion in the rumen, with different levels of response with different FM (McAllan, 1991). The aim of the experiment was to study the effects of supplementation with two FM, having the same nitrogen content (113 g N/kg DM) but different N rumen degradability, on fermentation and duodenal flow of nutrients.The study was carried out using six mature sheep fitted with rumen cannulae and single duodenal cannulae. Animals were fed 1 kg/d of a 60:40 hay:concentrate diet having a N content of 22 g/kg DM, either alone (Control; C) or supplemented with 40 g FM/d (FMl and FM2). The experiment was carried out over four periods of 14 days and in each period two sheep received each of the diets.

Effect of ruminally undegradable protein from fish meal on growth and reproduction of peripuberal Brahman bulls1

Thirty-nine Brahman bulls (301.7 +/- 4.1 d; 202.7 +/- 4.7 kg) were allotted to one of two treatments and fed soybean meal (SBM)- or fish meal (FIS)-based supplements and hay to examine the effects of source of protein on growth and reproductive development. The fish meal supplement had 72% ruminally undegradable protein (RUP) and the soybean meal supplement had 47% RUP. Bulls assigned to the FIS treatment had higher (P < .01) total weight gain (81.2 +/- 1.4 vs 71.2 +/- 2.2 kg), higher (P < .01) ADG (.97 +/- .02 vs .85 +/- .03 kg), and better (P < .05) feed:gain ratio (7.6 +/- .1 vs 8.6 +/- .1 feed/BW gain for FIS vs SBM, respectively). Age at first motile spermatozoa was not affected (P > .05) by source of protein (429.9 +/- 9.6 vs 427.2 +/- 9.5 d, for bulls receiving FIS or SBM supplements, respectively). Likewise, age at puberty (473.3 +/- 21.7 d vs 465.9 +/- 12.9 d for bulls receiving FIS and SBM supplements, respectively) was similar for both treatment groups. There were no differences between treatments in scrotal circumference at those stages. At puberty semen quality was similar for bulls receiving FIS or SBM treatments, and no differences existed in LH and testosterone concentrations between treatments. We conclude that fish meal supplement increased growth but did not alter reproductive parameters in Brahman bulls.

Effect of supplemental fish meal protein on site and extent of digestion in beef steers.

The effects of supplemental fish meal on site and extent of digestion were determined using four steers equipped with ruminal, duodenal, and ileal cannulas. Fish meal was included in diets to supply 0 (0FM), 25 (25FM), 50 (50FM), or 75 (75FM) g of N daily above the CP requirement of a 400-kg steer gaining 1.2 kg/d. Total tract starch digestibility tended to be greatest for 25FM (95%), lowest for 0FM (90%), and intermediate for 50FM (94%) and 75FM (92%). Total tract N digestibility was greatest for 25FM, lowest for 0FM, and intermediate for 50FM and 75FM (cubic, P < .05). Total tract starch digestibility increased .46 percentage units for each unit increase in N digestibility (n = 16, P = .03). Ruminal starch digestibility was greatest for 25FM, intermediate for 50FM and 75FM, and lowest for 0FM (quadratic; P < .10). Starch flow to the duodenum was decreased for 25FM and 50FM vs 0FM and 75FM (quadratic, P < .10) and N flow to the duodenum was increased (linear, P < .01) by fish meal. Fish meal supplementation increased N digestibility (quadratic, P < .05) but had no effect (P > .10) on starch digestibility in the small intestine. Starch digestibility in the small intestine was not related to N flow to the duodenum; however, starch digestibility increased .9 percentage units for each percentage unit increase in N digestibility (n = 16, P = .02). Fish meal supplementation tended to increase total tract starch digestibility by increasing ruminal, but not small intestinal, digestibility.

Effect of fish meal supplementation on body energy mobilization and milk production of ewes in negative energy balance

Protein supplementation has a positive effect on milk production, particularly in ewes on negative energy balance (Gonzalez et al., 1985). The response has been associated either to an increase in the movilization of body reserves (Whitelaw et al., 1986, Hadjipanayotou et al., 1988) or to an enhanced efficiency of energy utilization for milk synthesis. On the other hand, the response has been shown to be higher with fish meal than with other protein sources (Oldham, 1984). This work aimed to study the mecanisms involved in the response to fish meal supplementation, in lactating ewes on negative energy balance.

Effect of fish meal supplementation on body energy mobilization and milk production of ewes in negative energy balance

Protein supplementation has a positive effect on milk production, particularly in ewes on negative energy balance (Gonzalez et al., 1985). The response has been associated either to an increase in the movilization of body reserves (Whitelaw et al., 1986, Hadjipanayotou et al., 1988) or to an enhanced efficiency of energy utilization for milk synthesis. On the other hand, the response has been shown to be higher with fish meal than with other protein sources (Oldham, 1984). This work aimed to study the mecanisms involved in the response to fish meal supplementation, in lactating ewes on negative energy balance.

Effects of underfeeding and of fish meal supplementation on forage digestion in sheep

SUMMARYThe effects of severe food restriction and of protein supplementation on the apparent digestibility of a forage were studied on 12 wethers in 1992 at INRA, Theix. Ruminal digestion of the forage cell walls was studied in a second experiment carried out on four ewes fitted with rumen and duodenal cannulas, receiving the same diets as the wethers. The animals were fed on two different hay-based diets: hay only (58 or 25 g/kg BW0·75 per day) or hay supplemented with fish meal (48 or 20 g hay with 6·5 and 3·0 g fish meal respectively per kg BW0·75). The effects of fish meal supplementation on apparent digestibility of the hay cell walls were small, + 1·8 and + 2·3 units for neutral detergent fibre (NDF) and acid detergent fibre (ADF) respectively. In contrast, NDF and ADF digestibility was respectively 4·0 and 4·7 units higher at low than at high intake. Rumen fluid volume decreased by 2·4 1 with decreasing intake, while water concentration in rumen content increased slightly from 89·8 to 91·8%. The mean retention time of the hay particles in the foreguts increased concomitantly from 39·5 to 55·1 h. This was achieved by a higher retention time to a similar extent in both slow and fast compartments. The calculated in situ degradability of NDF and ADF increased respectively by 12·1 and 13·1 units with decreasing intake. This reflected the lower fractional outflow rate recorded at low intake. If a fractional outflow rate value of 4·1%/h (as measured in high intake diets) was applied to all dietary treatments, NDF and ADF in situ degradability would be greater at low than at high intake (31·7 v. 26·6% for NDF; 27·9 v. 22·1 % for ADF), indicating a higher microbial activity in restricted diets. Interactions between intake and fish meal supply were detected for in situ degradation parameters, indicating principally a reduction of the cell wall undegraded fraction in supplemented diets when intake declined. Ruminal fermentation was modified by the dietary treatments, the acetate: propionate ratio being higher at low intake. Fish meal increased concentrations of ammonia and of isoacids in rumen liquid. The relationship between apparent digestibility and in situ degradability of plant particles is discussed.

Lipid oxidation in meats of omega-3 fatty acid-enriched broiler chickens

Broiler chickens were fed a diet supplemented with 0, 4, 8 and 12% fish meal for 42 days. They were slaughtered under commercial conditions and the oxidative stability was assessed immediately after cooking and again after up to 4 days refrigerated storage. Oxidation was measured by using peroxide values and headspace hexanal concentrations. Omega-3 fatty acid incorporation in breast and thigh muscle lipids increased corresponding to fish meal in the diet. Headspace hexanal and peroxide values increased during 4 days of refrigerated storage with the highest values found in the chicken fed 8% and 12% fish meal diets. The peroxide values were higher for breast meat than for thigh meat but headspace hexanal was higher in thigh meat. Under the dietary conditions examined oxidation during refrigerated storage of cooked chicken appears to limit the amount of fish meal supplementation possible to 4%.

The influence of urea supplementation or treatment of rice straw and fish meal supplementation on rumen environment and activity in sheep

The rate and extent of degradation of dry matter (DM) of untreated rice straw (URS) was studied in four rumen environments created by feeding urea-supplemented rice straw (USRS) or urea-treated rice straw (UTRS) as basal diets with or without fish meal (FM) supplement. In addition the animals were given rice bran (RB) to form a straw to RB ratio of 70:30 and adequately supplemented with a mineral and vitamin premix. Four rumencannulated adult sheep in a 4 × 4 Latin square were used. Rumen pH, NH 3-N and volatile fatty acids (VFA) were measured in the same experiment. An incomplete but balanced 4 × 4 Latin square was used to measure the rate and extent of degradation of USRS and UTRS in the rumen of sheep where the same feeds were fed as basal diets. The results showed that the extent and rate of degradation of URS were more or less similar when incubated in the rumen of sheep fed the four treatment diets. Similarly, there was little difference in degradation between USRS and UTRS incubated in the rumen of sheep given these feeds as basal diets with or without FM supplementation. The UTRS was degraded to a higher degree than URS and USRS and this was reflected in a significantly ( P < 0.001) lower concentration of rumen NH 3-N in the two UTRS diets compared with USRS diets. The rumen pH and VFA concentrations did not show any differences between the four rumen environments. Although urea treatment and FM supplementation had been expected to show a stimulatory effect on microbial density and colonisation of cellulolytic bacteria it was not possible to detect any difference in the URS degradation between the four treatment diets. The reason may be that USRS together with 30% RB created an optimal rumen environment for rice straw degradation which was not improved by FM supplementation or by feeding the more degradable UTRS.

Performance of beef weaners on kikuyu silage supplemented with maize meal alone and in combination with protein of low degradability

AbstractA series of experiments were designed to evaluate the effect of supplementation of maize meal, alone or in combination with protein of low degradability, on the growth and voluntary intake of beef weaners.Experiment 1: Maize meal (energy supplement) alone or in combination with fish meal (undegradable protein supplement) were evaluated as kikuyu silage supplements. Average daily weight changes of −312, 73, 300, and 635 g were obtained in weaners which were fed silage with no supplementation, 1.5 kg maize meal, 3 kg maize meal and 1.25 kg maize meal plus 0.250 kg fish meal each day, respectively.Experiment 2: The effect of increasing levels of protein of low degradability, in the form of fish meal, as a supplement to kikuyu silage was evaluated. Voluntary intake increased with fish meal supplementation but not the level of supplementation. Weaners given 250 or 400 g of fish meal per weaner per day had higher liveweight gain than those not supplemented or supplemented with 100 g.Experiment 3: Cottonseed meal, milled full‐fat soya beans and corn gluten meal were evaluated as replacements for fish meal. All diets were isocalorific and with the exception of the soya bean diet, which was lower in undegradable protein than the others, all diets had identical quantities of calculated undegradable protein. Neither voluntary intake nor liveweight gain were significantly affected by the replacement of fish meal with cottonseed or corn gluten meals.

Effects of Dietary Protein Level on Growth and Body Composition of Channel Catfish Reared in Cage

Channel catfish fingerlings (84 g) were stocked in 1.25-m3 cages at a rate of 250 fish/cage and fed to satiety once daily with diets containing 27, 32, 37, or 42% protein for 12 weeks. The diets were similar to commercial formulations, composed of soybean meal, corn, fish meal, and vitamin and mineral supplements. The protein to energy ration (P/E) was increased by substituting soybean meal and fish meal (5:1) for corn. Fish meal constituted a fixed percentage (15%) of the total protein of the diets. Growth of channel catfish fed diets with increasing dietary protein levels was not significantly different (P > 0.05) among treatments. Average final weight, total length, survival, food conversion ratio (FCR), and specific growth rate (SGR were 312 g, 31.3 cm, 84.8%, 1.47 and 1.47%/day, respectively. Protein efficiency ratio (PER) as significantly higher (P < 0.05) for fish fed a diet containing 27% protein compared to fish fed the other three diets. Dressing percentage was not significantly different (P < 0...

Effect of Supplemental Fish Meal on the Lactation and Reproductive Performance of Dairy Cows

The influence of high protein diets (21% CP, DM basis), containing varied percentages of RUP, on lactation performance and fertility was evaluated. Sixty-two Holstein cows (65% multiparous) were blocked by age and randomly assigned to a 2 × 2 × 2 factorial design from d 12 to 125 postpartum. Factor 1 was 0 or 3.5% fish meal diet, factor 2 was location (Calan door versus free stall), and factor 3 was parity (first versus second or later). The soybean meal diet consisted of alfalfa hay, corn silage, barley, and soybean meal. The fish meal diet contained 3.5% fish meal (ruminant grade menhaden) that replaced a portion of the soybean meal.Cows fed the fish meal diet (40% RUP) had DMI, BW, and body condition similar to those of cows offered the soybean meal diet (34% RUP). Cows receiving the fish meal supplement tended to have higher milk protein production throughout the trial, higher milk production during the first 6 wk, and significantly lower ruminal ammonia concentrations than cows receiving the soybean meal diet. Differences in reproductive performance were not significant except for a diet by housing location interaction for conception rates from first AI.

Enzyme activities of rumen solid‐adherent microorganisms in chronically underfed ewes

AbstractFour ruminally cannulated ewes were used in a series of two crossover designs to investigate the effects of underfeeding and of supplementation with slowly degradable protein on polysaccharide and glycoside‐degrading enzyme activities in rumen solid‐adherent microorganisms. The ewes were fed twice daily on a hay based diet to satisfy either 1.2 or 0.5 maintenance energy requirements, with or without 125 and 65 g fish meal supplement for the high and the low intakes, respectively. Enzyme preparations were isolated from rumen solid contents 2, 6, and 12 h after feeding. Protein supplementation had no significant effect on the activity of any of the enzymes measured. The effects of feeding level on carboxymethycellulase and xylanase activities were small, the specific activity (expressed per mg microbial protein) being slightly increased at low intake (P &lt; 0.10). However, β‐D‐galactosidase, β‐D‐glucosidase, β‐D‐xylosidase, and β‐D‐cellobiosidase activities were considerably increased with low feeding level ( + 56 to +70% for specific activities; +31 to + 50% when expressed per g dry matter). The activities of all enzymes tested increased significantly with time after feeding. The extent of specific activity response to variation of feeding level was greater for late sampling times than 2 h post‐feeding. Ruminal degradation of the dietary bay was not affected by fishmeal supplementation, but increased with reduction of feeding level (+ 59.7 g kg−1 for neutral detergent fibre during the first 12 h of rumen incubation; P &lt; 0.001). The higher microbial efficiency associated with greater retention time of feed particles in the rumen may account for the increase in cell wall degradation usually observed when feeding level declines.

The Effect of Supplementary Protein on In Vivo Metabolism of the Mammary Gland in Lactating Dairy Cows

Four lactating cows equipped with rumen and duodenal cannulas were fed a diet of grass silage and concentrates containing either 12.4 or 17.2% CP (DM basis) in a change-over design. Additional protein was supplied as white fish meal. Fish meal did not affect molar proportions of VFA in the rumen, but duodenal NAN supply was increased .69 g/g of N in supplementary feed. In Experiment 2, three lactating dairy cows that had been prepared with catheters across the mammary gland were fed the same diets using a switchback design. Blood samples were taken to determine changes in metabolite flux to the mammary gland. In both experiments, milk production and protein yield were non-significantly increased by addition of fish meal. Milk urea output was increased from 3.18 to 4.74 g/d by fish meal supplementation, reflecting increased arterial concentrations of urea. Concentrations of glucose, VFA, and BHBA in blood showed no substantial changes because of dietary supplementation of fish meal. Supply of essential AA increased 26% with fish meal supplementation, mammary uptake increased 34%, but milk protein output only increased 5%. The low efficiency of conversion of supplementary protein to milk protein appears to be related to the inability of the gland to utilize the additional AA.

Growth and carcass quality of prolific crossbred lambs fed silage with fish meal or different amounts of concentrate.

Sixty Romanov x Dorset (RVDP) and sixty Romanov x Suffolk (RVSU) male lambs were used in a 2 x 5 factorial arrangement of treatments including two breed crosses and five diets to determine the effect of breed crosses on performance and to compare growth and carcass characteristics of lambs. Diets consisted of an all-silage diet, silage supplemented with 100 g of fish meal.animal-1.d-1, or silage supplemented daily with concentrate at either 200 g or 400 g per animal, or ad libitum intake. Lambs were fed from an initial weight of 23 kg to a slaughter weight of 45 kg. There was no interaction (P > .10) between diet and breed for any parameter measured. Silage DMI was decreased (P < .05) by supplementation, but total DMI was similar among diets. The ADG was increased by fish meal and concentrate supplementation, with higher (P < .05) ADG observed with ad libitum access to concentrate. Lambs that had ad libitum access to concentrate had an improved gain:feed and required less time to reach market weight but had more carcass fat than lambs fed other diets. Lambs fed only silage had a higher percentage of carcass with poorer muscling than others. The highest percentage of carcasses with excellent to good muscling, normal fat covering, and grades A1 and A2 was obtained with fish meal supplementation. Lambs from the RVSU-crossbreed had better ADG than RVDP lambs but carcass quality of RVDP lambs was better than that of RVSU lambs.(ABSTRACT TRUNCATED AT 250 WORDS)

Utilization of grass silage by cattle: effect of supplementation with different sources and amounts of protein1

Forty-eight crossbred beef steer calves, initial live weight of 260 kg, were used to examine production responses when grass silage was supplemented with fish meal (FM) or soybean meal (SBM) during a 210-d feeding period. The silage was available on an ad libitum basis either alone or supplemented with 100, 225, 350, or 500 g of FM or 600 g of SBM/d. Increasing levels of FM resulted in a linear increase in live weight gain (P < .001) and gain:feed ratio (P < .001). The FM supplementation had no effect (P = .79) on silage DM intake. The FM supplement increased plasma albumin concentration (P < .05) but did not affect plasma glucose (P > .20) The steers were shipped to market when they had 8 mm of fat over the longissimus muscle as determined by ultrasound. Sensory evaluation of roasts from steers fed 0, 225, 350, or 500 g/d of FM indicated a positive linear (P < .01) increase in flavor and decrease in juiciness as FM level increased. There were no differences (P > .15) in live weight gain, intake, or gain:feed ratio between isonitrogenous supplements of FM and SBM. However, the additional gain resulting from SBM and FM indicated that, on a crude protein basis, SBM was approximately 80% as effective as FM in increasing live weight gain in steers fed grass silage.

The Effect of Level of Supplement Feeding and Source of Protein on Milk Production and Nutrient Flows of Dairy Cows

Milk protein synthesis may be limited by amino acid (AA) flow to the duodenum. This can be increased by increasing the flow of microbial AA's or undegraded feed AA's. This experiment was carried out to determine the effect on milk production and nutrient flows at the duodenum of including fishmeal (120g/kg) in the supplement to grass silage at two levels of supplement feeding.The treatments, arranged in a 2x2 factorial, were 1.) 3.5 kg/day of 0% fishmeal supplement (L-UDP), 2.) 7 kg/day of L-UDP, 3.) 3.5 kg/day of 12% fishmeal supplement (H-UDP), and 4.) 7 kg/day of H-UDP. Supplements were fed to 3 6 Friesian cows in a 4x4 multiple Latin-square trial with three week periods to determine production responses, and to four ruminally and duodenally cannulated cows to determine rumen fermentation and nutrient flows. Flows were determined by the dual marker technique of Faichney (1975) using cobalt-EDTA and ytterbium acetate as liquid and solid phase markers respectively. Purines were used as the bacterial marker (Zinn and Owens, 1986). Degradability of the feeds was measured in 3 other cows using the small bag technique described by De Boer et al. (1987).

Protein supplementation of different silages for growing steers

Supplementation of silage diets with fish meal (a low rumen degradable protein) has resulted in increased live-weight gains in steers (England &amp; Gill, 1985). This response has been attributed to increased dietary protein escaping degradation in the rumen and being digested in the small intestine. Fish meal however is expensive in monetary terms. More recent work (Jacobs and McAllan, 1992) showed that rapeseed meal (a highly rumen degradable protein) supplementation of silage diets given to growing steers resulted in significant increases in live-weight gains similar to those obtained with fish meal supplements. The response to rapeseed meal was probably a result of enhanced microbial protein synthesis in the rumen as a result of synchrony of available energy and nitrogen nutrients, thus increasing microbial (and hence) total protein flow to the small intestines, producing a similar overall response to fish meal. The object of this experiment was to further evaluate the use of rapeseed meal as an alternative to fish mealTwo silages, 60D (low digestibility, L) and 70D (high digestibility, H) were prepared from minimum wilt first cut perennial ryegrass (mixed sward). The grass was cut with a disc mower and picked up with a precision chop harvester.