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1.
Male calves between 15 and 26 days old and with a live weight between 45 and 46 kg received dried skim milk dissolved in water plus fat concentration from lard--suet mixtures made with a synthetic emulsifier of the type ethoxylated partial ester with and without soybean lecithin supplement. One group received bone fat with an emulsifier as sole fat component. In the course of 9 experiment weeks the calves of the lard--suet group without lecithin reached an average daily weight gain of 710 g, which was not significantly better than the gains of 689 g of the lard--suet group with lecithin and of 674 g of the bone fat group. The calves of the lard--suet group with lecithin did not digest the feed fat significantly better than the calves in the other two groups. The quota of fatty acids in the feed distinctly influenced the composition of the fatty acids in the intestines, the kidneys and the hypodermis. With the example of suet the general relationship between the fatty acid patterns of the feed and body fats are recognizable, with the fatty acids C 16:0, C 18:2 and C 18:3 having a lower and C 16:1, C 18:0 and C 18:1 having a higher quota in the suet than in the feed fat. Due to the application of high amounts of bone fat, vegetable oil or sea animal fat there are deviations from this rule. There is a higher quota of linolenic acid in the suet of the calves than in butter fat but a lower quota than in foreign fat.  相似文献   

2.
The objective of this study was to determine the digestibility of milk lipids in calves with diarrhoea, the pathophysiological effects of fat intake on the course of the disease and the conversion of malabsorbed longchain fatty acids to secretory effective hydroxy fatty acids by the intestinal flora. Animals: 32 male calves of the breed "Deutsches Fleckvieh" with spontaneous occurring diarrhoea, age 3-14 days. Reference group: 6 clinically healthy calves of the same age group. Feed: whole milk, daily ration corresponding to 10% of the BM, divided into 3 meals; supplementary oral rehydration solution as required. METHODS: Quantitative collection of the faeces excreted over a period of at least 72 hours, determination of fatty acids and glycerides, identification and quantification of hydroxystearic acids in the faeces by gas chromatography; calculation of the apparent digestibility of the milk lipids. RESULTS: The apparent digestibility of the milk lipids was in part considerably reduced in direct relation (r = 0.8) to the severity of the diarrhoea. In the case of daily fecal outputs of over 50 g/kg BM (watery diarrhoea), the apparent fat digestibility was reduced below 50%. Even so, the apparent digestibility correlated positively with the milk intake (r = 0.5). The fat excretion in the patients showed an average of 1.4 g/kg BM/24 h and was thus nearly nine times higher in comparison to the reference group (0.16 g/kg BM/24 h). In the case of severe diarrhoea, fat excretion rates of over 2 (up to max. 5.8) g/kg BM in 24 hours were recorded. However, in the main (approx. 70%) it was not glycerides but nonesterified fatty acids. A part of the longchain fatty acids were converted to hydroxy fatty acids by the intestinal flora. It was possible to quantify alpha-, 10(9)- and 12-hydroxystearic acids individually in the faeces of both healthy calves and those with diarrhoea. However, the total concentration of hydroxystearic acids in the faces of 26 out of 32 patients was considerably under the secretory effective concentration of 2 mmol/kg (mean = 1.5 mmol/kg), the other six lay between 2.9 and 11.6 mmol/kg. Only a weakly positive correlation (r = 0.23 or 0.24) existed between the amount of milk intake and the fecal concentration resp. excretion of hydroxystearic acids. CONCLUSIONS: There was no evidence that the consumption of milk lipids influenced the diarrhoea negatively. In individual cases, it could not be completely excluded that fluid and electrolyte absorption was affected by hydroxystearic acids produced in the intestine, but the quantitative effects of this process are of minor significance in comparison to other diarrhoea inducing factors.  相似文献   

3.
Three experiments were conducted to determine whether emulsifiers improve utilization of fat from diets for early-weaned pigs. In Exp. 1, 96 weanling pigs (17 d old) were used in metabolism cages, with main effects of fat source (soybean oil, tallow, lard, and coconut oil) and emulsifier treatment (no emulsifier, lecithin, and lysolecithin as 10% of the added fat). Soybean oil and coconut oil were more digestible than tallow and lard (P < .001). Tallow was more digestible when lecithin and lysolecithin were added (P < .007), and pigs fed lecithin had lower serum triglycerides and cholesterol than pigs fed lysolecithin (P < .03). In Exp. 2, 270 weanling pigs (21 d old) were used in a growth assay. Treatments were 1) control diet; 2) Diet 1 with soybean oil; 3) Diet 1 with tallow; 4, 5, and 6) Diet 3 with lecithin replacing 5, 10, and 30% of the tallow, respectively; and 7, 8, and 9) Diet 3 with lysolecithin replacing 5, 10, and 30% of the tallow, respectively. At d 14 of the experiment, digestibility of tallow was improved more by lecithin than lysolecithin (P < .008). For the total experiment (d 0 to 35), the control pigs had poorer gain:feed ratio than did the pigs fed the fat sources (P < .002). In Exp. 3, 420 weanling pigs (21 d old) were used. Treatments were 1) control diet with soybean oil; 2) Diet 1 with tallow; and 3, 4, and 5) Diet 2 with 10% of the added fat as soybean oil, lecithin, or monoglyceride, respectively. Adding soybean oil, lecithin, and monoglyceride to tallow increased digestibility of total fat (P < .07). From d 0 to 14, pigs fed soybean oil gained weight faster than pigs fed the other treatments (P < .06), and pigs fed tallow without emulsifiers had the lowest ADG. Considering all experiments, addition of emulsifiers increased digestibility of nutrients but had minimal effect on growth performance.  相似文献   

4.
Dried whole whey, lard or dried skim milk was added to a corn-soybean meal basal diet to determine the effect on apparent nitrogen (ND), energy (ED) and dry matter digestibility (DMD) in pigs weaned at 28 d. Four groups of four littermate barrows were allotted to the experimental diets and placed in individual metabolism pens for 12 d (3 d adjustment and three collection periods of 3 d each) after weaning. The study was a 4 X 3 factorial with diet and period as main effects. Addition of dried skim milk or dried whey to the diet resulted in higher values (P less than .05) for DMD and ED as compared with the basal or corn-soy and lard diet. Pigs fed added dried skim milk had improved (P less than .05) ND over pigs on other dietary treatments. All nutrient digestibility coefficients increased (P less than .05) from period 1 to period 2, and ND increased (P less than .05) from period 2 to 3. It was concluded that the young pig requires at least 6 to 9 d after weaning at 28 d to adjust to typical corn-soybean meal starter diets.  相似文献   

5.
This paper describes the results from an experiment with four Jersey calves. The calves were bucket fed with a milk substitute consisting of skimmed milk powder and marine fat, supplemented with soyalecithin, vitamins and minerals. They were slaughtered after 30–32 days of such feeding. During the last two weeks a balance study was performed with a collection period of two days. Hay was given ad lib., and during the balance period the calves took between 125–150 g per day. The lipid content of the hay was considered negligible. Total content and distribution of fatty acids in the milk substitute are shown in Table 1. Table 2 shows the age of the calves, the total intake of lipid and fatty acids, and the total amount of fatty acids excreted with feces. The apparent digestibility coefficients of the individual fatty acids in each trial are shown in Table 3.  相似文献   

6.
The concentration of CLA in adipose tissue can be increased in ruminants by feeding pasture and extruded soybeans. The objective of this study was to evaluate maternal supplementation of raw (RS) or extruded (ES) soybeans on the concentrations of CLA in milk fat of cows and s.c. adipose tissue of suckling calves. Thirty-two spring-calving cows (BW 624 +/- 76 kg; BCS 3.5 +/- 0.4; mean +/- SD) and calves (BW 127 +/- 15 kg) were separated into 2 groups. Cows were distributed to have 8 calves of each sex in both groups. When animals were turned out to pasture, dams received 2 kg/d of either RS or ES. Dietary treatments had no effect on average milk intake (P = 0.22) and pasture forage intake (P = 0.13) for calves over the course of the grazing season. As a result, no effect of treatments was observed on ADG (P = 0.26). At weaning, milk fat content of CLA reached 15.4 and 24.2 mg/g of total fatty acids for cows fed RS and ES, respectively (P = 0.02). The CLA concentrations in adipose tissue were 16.9 and 25.0 mg/g of total fatty acids for calves suckling dams fed RS and ES, respectively (P < 0.001). Overall, results demonstrated supplementing grazing cows with ES increased CLA content in milk and adipose tissue of suckling calves.  相似文献   

7.
Two experiments were conducted with Polypay ewes nursing twin lambs to evaluate the effects of supplementing fat (calcium salts of palm oil fatty acids or hydrogenated tallow) on ewe lactation. In Exp. 1, ewes were fed a 52% concentrate:48% hay-based diet (as-fed basis) consisting of alfalfa hay (n = 4), endophyte-free fescue hay (n = 4), or fescue hay with 3.7% fatty acids (n = 4) from d 4 to 56 of lactation. In Exp. 2, ewes were fed similar diets that had endophyte-free fescue hay (n = 6), fescue hay with 3.7% fatty acids (n = 5), or fescue hay with 3.1% tallow (n = 6) from d 14 before lambing until d 57 of lactation. Diet formulations with supplemental fat were more nutrient dense, and treatments were fed to meet ewe nutrient requirements; this caused diets with added fat to be offered at 10 and 17% lower rates than unsupplemented diets in Exp. 1 and 2, respectively. Lambs were maintained to consume only ewe milk. Ewe milk production and composition were determined using a portable milking machine following a 3-h separation from lambs. In Exp. 1, milk fat content was increased (P < 0.01) when ewes consumed fescue hay with fatty acids vs. the fescue hay diet (11.4 vs. 8.3%). Ewes fed fescue hay with fatty acids lost the most (P < 0.05) weight over lactation (-8.6 kg) compared with ewes fed the alfalfa hay (-2.4 kg) and fescue hay (-3.8 kg) diets. Other milk measures, lamb gain, and production efficiencies were not changed. In Exp. 2, ewes supplemented with fatty acids produced more (P < 0.05) milk fat than those fed tallow (290 vs. 210 g/d). The proportion of synthesized milk fat 14:0 was decreased (P < 0.01), but the percentage of incorporated 16:0 increased (P < 0.05) when fatty acids were fed. Dietary fat digestibility by ewes was increased (P < 0.01) by fatty acid supplementation but decreased (P < 0.01) when tallow was added. Although ewe weight measures were not changed in Exp. 2, twin lamb gain per ewe organic matter intake was most efficient (P < 0.05) when ewes were supplemented with fatty acids. Results suggest that feeding hydrogenated tallow decreased nutrient availability for ewe milk fat production. A complete diet based on endophyte-free fescue hay can replace a traditional alfalfa hay diet, whereas supplementing with the calcium salts of palm oil fatty acids may be more feasible when energy is limiting during ewe lactation.  相似文献   

8.
Digestibility trials were carried out with calves, aged 3, 5, 7, 9, and 11 weeks, which were fed with feedstuffs of various energy and protein levels (various amounts of dried skim milk supplement with 146, 219, 323 g per day of the milk replacer Laktin) plus concentrate and hay. The purpose of the experiment was to find out what effect the amount of milk replacer varying daily had on the digestibility of the nutrients. The experiments confirm that the amount of milk replacer has a great influence on the digestibility of the crude fat. The amount of digestible crude fat consumed with the feed considerably influcenced the digestibility of the energy, it had little influence on the digestibility of the other nutrients, however. With increasing age the calves received more plant protein sources with a lower biologic value. Thus the digestibility of the protein in the complete ration was diminished as well. This shows that the digestibility was influenced by the protein quality, not, however, by the amount of crude protein. The digestibility of the dry matter andthe organic matter as well as of the N-free extractives in the feed ration diminished according to the changed composition with the increasing age of the animals; in constrast to this the digestibility of the crude fibres increased gradually.  相似文献   

9.
1. The utilisation of fat and fatty acids supplied as maize oil, tallow or lard in the diet of 2-, 4- and 8-week old turkeys has been investigated: a mixture of 10% fat and 15% cellulose replaced glucose monohydrate in a low-fat basal diet. 2. At 2 weeks of age the absorbabilities of the fats were 96, 57 and 91% for maize oil, tallow and lard respectively; at 4 and 8 weekds of age the corresponding figures were 97, 70 and 92% and 98, 74 and 90%. 3. The unsaturated fatty acids (18:1, 18:2) were highly absorbed from all fats; this was true also of the saturated acids (16:0, 18:0) in the maize oil, but in lard and, especially, tallow the absorbability of these fatty acids was lower. 4. The effect of age on the utilisation of tallow could be explained by the improvement in the absorption of these fatty acids. 5. The determined and calculated ME values of the fats are given.  相似文献   

10.
24 calves of the breed "Deutsche Schwarzbunte Rasse" were used for qualitative and quantitative investigations on the metabolism of fatty acids, particularly that of linoleic acid. The trial comprised 6 calves in 4 groups. The experimental rations consisted of powdered skim milk, oat meal, milk sugar, coco fat and varying proportions of linoleic acid (1.0%, 1.5%, 2.5%). The control group received the basal ration without supplements of linoleic acid. After a short period of adjustment the metabolic trial was started with 9 periods each lasting 7 days. The composition of fatty acids in the faecal lipids was analysed by gas chromatography. The studies led to the conclusion that the fatty acids contained in the faecal fat were not immediately derived from the dietary fat. The results of the trial also showed that the major proportion of all the fatty acids present in the faecal lipids consisted of only 4 fatty acids, viz. oleic acid, palmitic acid, lauric acid and myristic acid. Changes observed for the content of linoleic acid in faecal lipids were negligible so that the assumption may be made that all of the linoleic acid added was completely digested.  相似文献   

11.
1. Two experiments were designed to study the influence of free fatty acid content and degree of saturation of free fatty acids and neutral fat on digestibility of added fats and fatty acids. Sunflower oil and tallow were used as neutral fats, and palmitic, stearic, oleic and linoleic acids as free fatty acids. Fat inclusion was 80 g/kg and mixtures of each fat and each free fatty acid were prepared in the proportions 100:0, 70:30 and 40:60.

2. Experimental diets were evaluated for fat and fatty acid digestibilities with broiler chickens at 21 d of age. The metabolisable energy of fat was calculated from the product of digestibility and gross energy. Increasing concentrations of saturated free fatty acids decreased the ME of added fat, whereas unsaturated free fatty acids did not significantly affect the ME value of added fat.

3. Digestibilities of individual fatty acids were analysed by linear regression with rate of inclusion of free fatty acid in the fat blend: palmitic and stearic acids gave a negative slope, whereas oleic and linoleic acids gave a slope not statistically different from zero. Because slopes for saturated fatty acids did not differ between the sunflower oil and tallow treatments, synergism between unsaturated and saturated fatty acids was not detected.  相似文献   


12.
Nutrient digestibility, metabolic effects and performance were evaluated in lactating cows (n = 6 × 6) receiving diets containing one of four different lecithins (raw, deoiled and deoiled/partially hydrolysed soy lecithin, raw canola lecithin) or soybean oil in combination with Ca soaps of palm oil fatty acids in a ratio of 1 : 3. A diet supplemented only with Ca soaps served as a control. The complete diets consisted of forage and concentrate (0.62 : 0.38) and total lipid supplementation was 30 g fatty acids/kg dietary dry matter. Lecithins had no effect on milk yield and milk composition. Apparent digestibility of dry matter, organic matter and gross energy were highest in the control diet and lowest in the soybean oil diet (p < 0.1) with intermediate values for the lecithin‐supplemented diets. Soybean oil particularly reduced fibre digestibility (significant with hemicellulose), whereas this effect was reduced or even missing when lecithins, particularly raw canola lecithin and deoiled/hydrolysed soy lecithin, were used. The digestibility of total fatty acids was not affected by the treatments. The effects were also not significant for blood plasma traits except for insulin which was significantly higher with raw than with deoiled/hydrolysed soy lecithin. In conclusion, lecithins, particularly those technologically modified or of a low polyenoic fatty acid content, might be preferred to oils when used as an energy source whereas they failed to improve digestibility of rumen‐protected fats.  相似文献   

13.
Two experiments were conducted to evaluate supplementation of diets with 8% corn oil, lard or tallow. In Exp. 1, 36 barrows weaned at 21 d of age were used to evaluate the effects of these three diets on digestibilities of fat and dry matter and subsequent N retentions from wk 1 to 4 postweaning. In Exp. 2, 147 weanling pigs in six replicates were used to evaluate weekly growth and feed performance measurements when fed these same diets for a 4-wk postweaning period. A large quantity of fat was absorbed (P less than .01) during wk 1 postweaning by pigs fed the corn oil diet, with the quantity absorbed similar for the three sources of fat from wk 2 to 4. Diets with corn oil had a higher apparent fat digestibility than diets supplemented with lard or tallow during each week postweaning (P less than .05). Apparent digestibility of fat increased (P less than .01) for each fat source each week postweaning but appeared to reach a plateau by wk 3 postweaning. Differences in apparent digestibility of fat between fat sources narrowed from wk 1 to wk 4, with digestibility of corn oil increasing from 79 to 89% and of animal fat sources increasing from 67 to 84%. Apparent digestibility of dry matter tended (P less than .10) to be highest when corn oil was provided during the initial 2-wk postweaning period. Although N retention was highest during wk 1 postweaning when the corn oil was fed, this response was attributed to the higher feed intakes of pigs fed this diet.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

14.
A balance trial was conducted to titrate the effects of tallow on the energy metabolism of wethers fed barley finishing diets. Six dietary levels of tallow (0, 2, 4, 6, 8, or 10%) in a barley finishing diet were fed to six crossbred wethers (35+/-1.1 kg) in a randomized complete block design. Diets were 73% barley, 10% tallow and(or) bentonite, 10% alfalfa pellets, and 7% supplement. There was no effect of tallow level on OM intake (1,103.1+/-51 g/d), OM digestibility (84+/-0.9%), GE digestibility (83+/-1.1%), or cell solubles digestibility (84.2+/-1.2%). The level of tallow quadratically decreased ADF digestibility (P < 0.05), methane emissions, and methane energy as a percentage of GE P < 0.01). There were linear increases in dietary GE (megacalories per kilogram of OM [P < 0.01]), dietary DE (megacalories per kilogram of OM [P < 0.05]), and dietary ME (megacalories per kilogram of OM [P < 0.01]), as dietary tallow increased. Numbers of ruminal protozoa (Entodinium spp. and Polyplastron sp.) decreased linearly (P < 0.05) with increased level of tallow. The energy value of tallow (calculated by difference) was low. The total-tract fatty acid digestibility of tallow was calculated by linear regression, without intercept, after accounting for the fatty acids digested from the base diet (0% tallow fed to a wether in a period). Fatty acids of the same carbon length were pooled for the regression analysis. All linear regressions were significant (P < 0.10) indicating no effect of tallow level on fatty acid digestibility. Lauric acid had low digestibility. The high digestibility of all C16 (89%) and C18 (104%) fatty acids suggests an effect of tallow on endogenous and microbial fatty acid excretion. Fatty acid digestibility was probably a minor contributor to the low energy content of tallow, calculated by difference, in these diets.  相似文献   

15.
This study was conducted to investigate the quantitative and qualitative changes in dietary and endogenous protein components along the small intestine of calves. They were fed milk replacers in which protein was provided either by skim milk powder alone, as control diet, or by skim milk powder and a soy concentrate, a partially hydrolyzed soy protein isolate, or a potato protein concentrate (1:1 on a CP basis). The calves were continuously infused with the liquid milk substitute diets into the abomasum. Duodenal, jejunal, and ileal digesta were collected through T-piece cannulas. Digestibility (corrected for total endogenous protein) of dietary protein and the concentration of dietary, host endogenous, and bacterial proteins were estimated from the AA composition of digesta using multiple linear regression. The apparent digestibility of feed components increased linearly between the duodenum and the ileum. It was lower with the diets containing plant protein than with the control, especially at the ileum (85% for CP with soy concentrate, 73% with soy isolate, and 81% with potato concentrate vs 91% with skim milk powder). The real digestibility of dietary protein at the ileum was estimated to be 96, 95, 94, and 99%, respectively, for each of the dietary components. The partition of protein components in digesta between dietary, nonspecific endogenous, specific host endogenous, and(or) specific bacterial proteins varied along the small intestine and between diets at a given site. Intestinal apparent reabsorption of host endogenous protein was estimated to be equivalent to at least 86% of the jejunum flow. To conclude, the lower apparent digestibility of the plant protein sources studied resulted more from an enhanced loss of host and bacterial endogenous proteins than from decreased hydrolysis of dietary protein and absorption of their AA.  相似文献   

16.
试验评估不同水平柑橘渣对奶牛泌乳性能、养分消化及乳成分的影响.将32头泌乳性能一致的奶牛随机分为4个组,每组4个重复,每个重复2头.对照组饲喂粗脂肪水平为3％的日粮,处理组分别饲喂粗脂肪水平为5.5％的日粮同时添加0 (T1)、5％(T2)和10％ (T3)柑橘渣.结果 显示,与对照组相比,处理组奶牛的粗脂肪摄入量、干...  相似文献   

17.
Eight male Holstein calves 7 to 10 d of age were fed a milk replacer containing a skim milk powder subjected to low-temperature drying either with or without addition of an oxalate-NaOH buffer known to prevent curd formation. The calves were used in a completely randomized design to study the effect of milk clotting on digestibility and blood parameters. Plasma glucose and plasma insulin were similar (P greater than .05) for the clotting and the nonclotting milk replacers. For both treatments, concentrations of glucose and insulin reached a peak 2 h postfeeding (P less than .01). Plasma triglycerides were higher (P less than .01) postfeeding for the nonclotting than for the clotting milk replacer. Plasma essential amino acids and plasma urea were higher, whereas plasma calcium was lower, for the nonclotting milk (P less than .01). Digestibility of dry matter, protein and fat was similar (P greater than .05) between clotting and nonclotting milk. The dry matter content of feces was not affected by clotting (P greater than .05). The data are interpreted to indicate that clotting of the milk replacer modifies blood concentrations of triglycerides, essential amino acids and urea without changing the digestibility of the diet.  相似文献   

18.
Four in vitro trials were conducted to determine how ruminal fermentation is affected by source of fat, level of fat, and combinations of fatty acids. Trials I and II examined how volatile fatty acids (VFA) were changed by three sources of fat (blended animal-vegetable fat, corn oil and tallow fatty acids) each added to a hay substrate at six levels (0, 2, 4, 6, 8 and 10%). Increasing blended fat caused no changes in VFA levels except to decrease butyric acid from 12.1 to 9.9% of the total VFA (P less than .05). Corn oil and tallow fatty acids both increased propionic acid, causing the ratio of acetic to propionic acids (A/P) to decrease (P less than .01). Trial III tested different ratios of oleic/stearic and linoleic/stearic acids to determine if certain combinations were better for fermentation. There was no evidence of synergism among fatty acids since increasing the ratio of unsaturates steadily reduced A/P. Trial IV was designed to determine how changes in VFA levels reflect changes in fiber digestibility of substrates containing added fat. Volatile fatty acids having significant regressions with fiber digestibility were acetic acid (r = .648), propionic acid (r = -.670), total VFA concentration (r = .742) and A/P (r = .831). Results are interpreted to show that blended animal-vegetable fats are less toxic in the rumen than equal levels of other lipids, and the beneficial effects of blended fat cannot be attributed to a unique combination of fatty acids acting synergistically.  相似文献   

19.
This experiment was designed to examine changes in milk fatty acids during fish oil-induced milk fat depression (MFD) and to test the theory that these changes are related to milk fat fluidity. The experiment was divided into three periods: 1) Baseline: all cows (n = 12) received a high fiber diet without fish oil (FO) for 12 days; 2) Treatment: 4 cows/group received the following treatments for 21 days: a) Low fiber diet without FO (LF), b) High fiber diet + FO (HF + FO) and c) Low fiber diet + FO (LF + FO); 3) Post-treatment: cows returned to the baseline diet and were monitored for 12 days. FO was included at 1.6% DM and HF and LF diets had 40 and 26% NDF, respectively. Milk fat content and yield were unchanged by the LF diet, but were reduced by FO diets at both dietary fiber levels and recovered in the post-treatment period. FO diets caused a pronounced reduction in stearic and oleic acid concentrations in milk fat and an equally pronounced increase in trans-18:1 fatty acid concentrations. Milk fat mean melting point (MMP) was correlated with MFD (r = 0.73) and with milk oleic acid concentration (r = − 0.92). The ratio of oleic:stearic in milk fat increased gradually and consistently in response to FO. Trans-C18:1 isomers with double bounds at carbon ≤ 10 increased with greater MFD and those with double bonds at carbon ≥ 11 decreased with greater MFD. Trans-9 cis-11 CLA explained more than 80% of MFD and was strongly correlated with trans-10 C18:1. Maintenance of MMP below 39–40 °C suggests that the mammary gland was able to secrete only milk fat with adequate fluidity and that MFD could be an adaptation mechanism to prevent secretion of milk with higher MMP.  相似文献   

20.
A complete two by two by four factorial design was used to examine the main effects of dietary fat type (10% soya oil or 10% beef tallow), xylanase supplementation (with or without Avizyme 1300 at 1 g/kg diet) and pentosan level (7.7 g/kg, 11.0 g/kg, 14.3 g/kg and 17.6 g/kg soluble pentosans, respectively, by varying wheat/rye proportions) as well as their interactions on intestinal chyme conditions, nutrient digestibility and nutrient utilization in male broilers. Nutrient digestibilities for the total digestive tract and at various sites of small intestine were measured during the period from day 18 to 20 of age and at day 21 of age, respectively, using a marker technique. Jejunal and ileal supernatant viscosity increased in an exponential manner as dietary pentosan concentration was increased. This increase was more pronounced in tallow fed birds but was also found in enzyme treated groups albeit at a much lower level. Xylanase activity was still detectable in the ileum of birds fed enzyme supplemented diets but its activity was found to decrease as dietary pentosan content increased. Digestibility of crude protein and that of some amino acids at the terminal ileum was decreased as dietary pentosan content was increased and significantly improved by xylanase addition. No fat effect and no interactions were detected at this site. In contrast, measurements made over the whole gastrointestinal tract showed significantly lower protein and amino acid digestibility values for tallow fed birds, and significant higher enzyme effects especially in diets with higher pentosan concentrations. Nitrogen-corrected apparent metabolizable energy (AMEN) content and net protein utilization decreased with increasing dietary pentosan content and were significantly improved by xylanase addition and were lower in tallow fed birds. Again, xylanase effects were found to be more pronounced for tallow fed birds and at higher pentosan concentrations.  相似文献   

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