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1.
Two experiments were conducted to investigate the relationships between amino acids and DE for pigs weighing 20 to 50 kg. In Exp. 1, there were three dietary lysine levels that were either adjusted (1.50, 2.35 and 3.20 g/Mcal DE) for five DE levels (3.00 to 4.00 Mcal/kg) or unadjusted (.45, .71 and .96% of the diet) for three DE levels (3.50 to 4.00 Mcal/kg). In Exp. 2, diets containing six lysine:DE ratios (1.90 to 3.90 g/Mcal) at two DE levels (3.25 and 3.75 Mcal/kg) were fed. Pigs were housed individually, and could eat and drink ad libitum. When pigs weighed 50 kg, their empty body composition was determined by the urea dilution technique in Exp. 1 and by prediction equations based on backfat in Exp. 2. For the adjusted diets in Exp. 1, protein deposition and protein deposition:DE intake increased (P less than .01) slightly as DE levels increased. These criteria decreased linearly (P less than .001), and fat deposition increased (P = .11) as DE increased when lysine:DE ratios were not maintained. As lysine levels increased, protein deposition and protein deposition: DE intake increased (P less than .001) in both the adjusted and unadjusted diets. In Exp. 2, there was no effect of DE on either the rate or efficiency of protein deposition. Both protein deposition and protein deposition:DE intake increased (P less than .001) and fat deposition decreased as lysine:DE ratios increased up to 3.00 g lysine/Mcal DE. Protein deposition: lysine intake decreased (P less than .01) progressively as the lysine:DE ratio increased. Regression analyses indicated the protein deposition increased up to 3.00 g lysine/Mcal DE. The results demonstrate the need to adjust lysine according to energy levels and indicate that the optimum ratio for protein deposition was approximately 3.00 g lysine/Mcal DE (or 49 g of balanced protein/Mcal DE).  相似文献   

2.
Growing goats, 45 Alpine and 45 Nubian, were used in a 3 x 3 factorial arrangement to quantify the influence of dietary energy and protein levels on daily DM intake and nutrient utilization for growth. Goats had ad libitum access to complete mixed diets containing either 2.46, 2.77 or 3.05 Mcal/kg ME plus 11.2, 12.7 or 15.1% CP for 16 wk. Dry matter intake decreased curvilinearly as dietary ME density increased (P less than .001). Dry matter intake increased linearly (P less than .05) as dietary CP level increased during all growth intervals except wk 25 to 28 of age. Average daily gain was 115, 113 and 99 g/d for goats fed diets containing 2.46, 2.77 and 3.05 Mcal/kg ME, respectively. Average daily gain was 104, 106 and 117 g/d for goats fed diets with 11.2, 12.7 and 15.1% CP, respectively. Dry matter intake was higher (P less than .01) for Alpine than for Nubian goats, whereas ADG was similar between breeds. Intake of ME was 248, 260 and 198 kcal/(kg.75.d) for goats fed the low- medium- and high-energy diets, respectively. Intake of CP was 9.1, 10.7 and 13.2 g/(kg.75.d) for goats fed low-, medium- and high-protein diets, respectively. Average requirements for growth derived from regression analysis of all data points were 4.6 kcal ME and .26 g CP/g ADG. The prediction equation for intake of growing goats of 4 to 8 mo of age was: DMI, g/d = 1,749 - 496 DE, kcal/g + 18 live weight, kg + 3 ADG, g/d; r2 = .73 (Sy.x = 127, P less than .0001, n = 90). The requirement of ME for growth was 33% lower than the value recommended in 1981 by the National Research Council.  相似文献   

3.
This study was conducted to evaluate the effects of dietary energy density and weaning environment on pig performance. Treatment diets were formulated to vary in DE concentration by changing the relative proportions of low (barley) and high (wheat, oat groats, and canola oil) energy ingredients. In Exp. 1, 84 pigs in each of 3 replications, providing a total of 252 pigs, were weaned at 17 x 2 d of age and randomly assigned to either an on-site or an off-site nursery and to 1 of 3 dietary DE concentrations (3.35, 3.50, or 3.65 Mcal/kg). Each site consisted of a nursery containing 6 pens; 3 pens housed 7 barrows and 3 housed 7 gilts. All pigs received nontreatment diets in phase I (17 to 19 d of age) and phase II (20 to 25 d of age), respectively. Dietary treatments were fed from 25 to 56 d of age. Off-site pigs were heavier at 56 d of age (23.4 vs. 21.3 kg; P < 0.05) and had greater ADFI (0.77 vs. 0.69 kg/d; P < 0.01) than on-site pigs. There was a linear decrease in ADG (P < 0.01) and ADFI (P < 0.001) with increasing DE concentration. Efficiency of gain improved (P < 0.01) with increasing DE concentration. There was no interaction between weaning site and diet DE concentration, indicating that on-site and off-site pigs responded similarly to changes in diet DE concentration. In Exp. 2, nutrient digestibility of the treatment diets used in Exp. 1 was determined using 36 pigs with either ad libitum or feed intake restricted to 5.5% of BW. Energy and N digestibility increased (P < 0.001) with increasing DE concentration. Nitrogen retention and daily DE intake increased with DE concentration in pigs fed the restricted amount of feed (P < 0.05). These results indicate that weaning off-site improves pig weight gain. The weanling pig was able to compensate for reduced dietary DE concentration through increased feed intake. Growth limitation in the weanling pig may not be overcome simply by increasing dietary DE concentration.  相似文献   

4.
A total of 335 lactating sows (Landrace × Large White) were used in two experiments to determine the optimum ratio of standardized ileal digestible lysine (SID-Lys) to metabolizable energy (ME) for mixed parity sows during lactation. In Exp. 1, 185 sows (weighing an average of 256.2 ± 6.5 kg and having an average parity of 3.4 ± 0.3) were allocated to one of six experimental diets in a completely randomized block design within parity groups (1, 2, and 3+). The experimental diets were formulated to contain 3.06, 3.16, 3.20, 3.25, 3.30 or 3.40 Mcal/kg of ME and each diet was fed to the sows throughout a 28 day lactation. All diets provided a similar SID-lysine level (0.86%). As a result, the diets provided a SID-Lys:ME ratio of 2.81, 2.72, 2.69, 2.65, 2.61 or 2.53 g/Mcal ME. Sow feed intake was significantly (P < 0.01) affected by the energy content of the diet as well as by sow parity. Using regression analysis, feed intake was shown to be maximized at 3.25, 3.21, 3.21 and 3.21 Mcal/kg of ME for parity 1, 2, 3+ sows and the entire cohort of sows respectively (quadratic; P < 0.01). In addition, the result of feed intake can be expressed as 2.65, 2.69, 2.69 and 2.68 g/Mcal based on analysis of SID-Lys:ME ratio. Litter weight gain was affected by dietary treatment for parity 3+ sows and the entire cohort (P < 0.01). Based on regression analysis, litter weight gain was maximized at 3.25 and 3.24 Mcal/kg of ME for parity 3+ (quadratic; P < 0.01) and the entire cohort (quadratic; P < 0.01). Similarly, the result of litter weight gain could be expressed as 2.65 and 2.66 g/Mcal of SID- Lys:ME ratio. Therefore, 3.25 Mcal/kg of ME was selected for Exp. 2 in which 150 sows (weighing 254.6 ± 7.3 kg and having an average parity of 3.4 ± 0.4) were allocated to one of five treatments in a completely randomized block design within parity (1, 2, and 3+). The experimental diets were formulated to contain 2.1, 2.4, 2.7, 3.0 or 3.3 g/Mcal of SID-Lys:ME ratio with all diets providing 3.25 Mcal/kg of ME. The diets were fed to the sows throughout a 28 day lactation. Sow body weight loss was affected by dietary treatment (parity 3+ sows, P = 0.02; entire cohort, P < 0.01) and by sow parity (P < 0.01). Litter weight at weaning and litter weight gain were affected by dietary treatment for parity 1, 2, 3+ sows and the entire cohort (P < 0.01) as well as by sow parity (P < 0.01). Plasma urea nitrogen (P < 0.01), creatinine (P < 0.01) and non-esterifide fatty acids (P = 0.04) were decreased as the SID-Lys:ME ratio of the diet increased. Insulin-like growth factor-1 (P = 0.02), estradiol (P < 0.01) and luteinizing hormone (P = 0.02) were increased as the SID-Lys:ME ratio in diet increased. Based on a broken-line model, the estimated SID-Lys: ME ratio to maximize litter weight gain was estimated to be 3.05 g/Mcal.  相似文献   

5.
ABSTRACT: A total of 335 lactating sows (Landrace × Large White) were used in two experiments to determine the optimum ratio of standardized ileal digestible lysine (SID-Lys) to metabolizable energy (ME) for mixed parity sows during lactation. In Exp. 1, 185 sows (weighing an average of 256.2 ± 6.5 kg and having an average parity of 3.4 ± 0.3) were allocated to one of six experimental diets in a completely randomized block design within parity groups (1, 2, and 3+). The experimental diets were formulated to contain 3.06, 3.16, 3.20, 3.25, 3.30 or 3.40 Mcal/kg of ME and each diet was fed to the sows throughout a 28 day lactation. All diets provided a similar SID-lysine level (0.86%). As a result, the diets provided a SID-Lys:ME ratio of 2.81, 2.72, 2.69, 2.65, 2.61 or 2.53 g/Mcal ME. Sow feed intake was significantly (P < 0.01) affected by the energy content of the diet as well as by sow parity. Using regression analysis, feed intake was shown to be maximized at 3.25, 3.21, 3.21 and 3.21 Mcal/kg of ME for parity 1, 2, 3+ sows and the entire cohort of sows respectively (quadratic; P < 0.01). In addition, the result of feed intake can be expressed as 2.65, 2.69, 2.69 and 2.68 g/Mcal based on analysis of SID-Lys:ME ratio. Litter weight gain was affected by dietary treatment for parity 3+ sows and the entire cohort (P < 0.01). Based on regression analysis, litter weight gain was maximized at 3.25 and 3.24 Mcal/kg of ME for parity 3+ (quadratic; P < 0.01) and the entire cohort (quadratic; P < 0.01). Similarly, the result of litter weight gain could be expressed as 2.65 and 2.66 g/Mcal of SID-Lys:ME ratio. Therefore, 3.25 Mcal/kg of ME was selected for Exp. 2 in which 150 sows (weighing 254.6 ± 7.3 kg and having an average parity of 3.4 ± 0.4) were allocated to one of five treatments in a completely randomized block design within parity (1, 2, and 3+). The experimental diets were formulated to contain 2.1, 2.4, 2.7, 3.0 or 3.3 g/Mcal of SID-Lys:ME ratio with all diets providing 3.25 Mcal/kg of ME. The diets were fed to the sows throughout a 28 day lactation. Sow body weight loss was affected by dietary treatment (parity 3+ sows, P = 0.02; entire cohort, P < 0.01) and by sow parity (P < 0.01). Litter weight at weaning and litter weight gain were affected by dietary treatment for parity 1, 2, 3+ sows and the entire cohort (P < 0.01) as well as by sow parity (P < 0.01). Plasma urea nitrogen (P < 0.01), creatinine (P < 0.01) and non-esterifide fatty acids (P = 0.04) were decreased as the SID-Lys:ME ratio of the diet increased. Insulin-like growth factor-1 (P = 0.02), estradiol (P < 0.01) and luteinizing hormone (P = 0.02) were increased as the SID-Lys:ME ratio in diet increased. Based on a broken-line model, the estimated SID-Lys:ME ratio to maximize litter weight gain was estimated to be 3.05 g/Mcal.  相似文献   

6.
The effects of diet and climate were assessed in 42 light horse weanlings over 30 wk. Horses were fed diets varying in energy and phosphorus content. Diets were predominantly forage (73 to 77.5%) or concentrate (62 to 62.25%) and had 2.65 or 3.09 Mcal DE/kg DM, respectively. Horses were weighed every 14 d. Group feed intakes and climatic variables were recorded daily. Dietary phosphorus content did not affect intake or gain. Horses fed forage diets ate 18% more (P less than .001) DM than horses fed concentrate, but DE intakes did not differ. Average DE intakes, 21.5 Mcal daily, were 33% more than those given in 1978 National Research Council (NRC) tables. Overall ADG by forage- and concentrate-fed horses were .83 and .89 kg, respectively. These values were 23 and 32% above mean ADG values given for horses at 6 and 12 mo in 1978 NRC tables. Average daily gain declined (P less than .01) with age, although daily DE intake increased (P less than .01). Total DM and DE intakes were determined largely by body weight, but age was the main determinant of weight-scaled DE intake. Weight- and age-scaled DE intakes were reduced (P less than .001) by 6.1% at temperatures below -10 degrees C compared with temperatures above -10 degrees C. Temperatures below -20 degrees C had no greater effect on DE intake than those between -10 to -20 degrees C. Neither precipitation nor wind alone affected weight- and age-adjusted DE intake. In conclusion, weanling horses fed readily digested diets ad libitum gained weight at or above expected values even at severely cold ambient temperatures.  相似文献   

7.
The objectives of this study were: 1) to determine if dietary protein reduction or oathull fiber inclusion would reduce urinary N excretion in grower pigs, 2) to determine if plasma urea could predict urinary N excretion among diets differing in protein and fiber content with an expected range in N excretion patterns, and 3) to determine the postprandial time point to sample blood for the best prediction. Three dietary protein concentrations (high, 19.7; medium, 16.9; low, 13.8%) and two fiber levels (high, 5.0; low, 3.6% crude fiber) were tested in a 3 x 2 factorial arrangement. Diets (wheat, barley, soybean meal; oathulls as fiber source) were formulated to 3.25 Mcal of digestible energy (DE)/kg and 2.2 g of digestible lysine/Mcal DE for low- and medium-protein diets, and 2.4 g/Mcal of DE for high-protein diets, and supplemented with lysine, methionine, tryptophan, threonine, isoleucine, or valine to meet an ideal amino acid profile. Pigs (32 +/- 3.4 kg; n = 42) were housed in metabolism crates for 19 d. On d 10 or 11, catheters were installed by cranial vena cava venipuncture. Daily feeding allowance was adjusted to 3x maintenance (3 x 110 kcal DE/kg body weight(0.75)), and was fed in two equal meals. Feces and urine were collected from d 15 to 19. Five blood samples were collected in 2-h intervals on d 16 and 19. Fecal, urinary, and total N excretion was reduced linearly with a reduction of dietary protein (P < 0.001); the reduction was greater for urinary (48%) and total N excretion (40%) than for fecal N excretion (23%). Similarly, the ratio of urinary to fecal N was reduced linearly with a reduction of dietary protein (P < 0.001). Retention of N (g/d) was reduced linearly, but N retention as a percentage of N intake was increased linearly with a reduction of dietary protein (P < 0.001). The addition of oathulls did not affect N excretion patterns and plasma urea (P > 0.10). Dietary treatments did not affect average daily gain or feed efficiency (P > 0.10). A dietary protein x time interaction affected plasma urea (P < 0.001). For medium- and high-protein diets, plasma urea increased postprandially, peaking 4 h after feeding, and then decreased toward preprandial levels (P < 0.05). Plasma urea did not alter postprandially for the low-protein diet (P > 0.10). Urinary N excretion (g/d) was predicted by 3.03 + 2.14 x plasma urea concentration (mmol/L) at 4 h after feeding (R2 = 0.66). Plasma urea concentration is indicative of daily urinary N excretion and reduction of dietary protein is effective to reduce total and urinary N excretion.  相似文献   

8.
We conducted two experiments to evaluate the effects of dietary energy density and lysine:calorie ratio on the growth performance and carcass characteristics of growing and finishing pigs. In Exp. 1, 80 crossbred barrows (initially 44.5 kg) were fed a control diet or diets containing 1.5, 3.0, 4.5, or 6.0% choice white grease (CWG). All diets contained 3.2 and 2.47 g of lysine/Mcal ME during growing (44.5 to 73 kg) and finishing (73 to 104 kg), respectively. Increasing energy density did not affect overall ADG; however, ADFI decreased and feed efficiency (Gain:feed ratio; G:F) increased (linear, P < .01). Increasing energy density decreased and then increased (quadratic, P < .06) skinned fat depth and lean percentage. In Exp. 2, 120 crossbred gilts (initially 29.2 kg) were used to determine the effects of increasing levels of CWG and lysine:calorie ratio fed during the growing phase on growth performance and subsequent finishing growth. Pigs were fed increasing energy density (3.31, 3.44, or 3.57 Mcal ME/kg) and lysine:calorie ratio (2.75, 3.10, 3.45, or 3.80 g lysine/Mcal ME). No energy density x lysine:calorie ratio interactions were observed (P > .10). Increasing energy density increased ADG and G:F and decreased ADFI of pigs from 29.5 to 72.6 kg (linear, P < .05). Increasing lysine:calorie ratio increased ADG and ADFI (linear, P < .01 and .07, respectively) but had no effect on G:F. From 72.6 to 90.7 kg, all pigs were fed the same diet containing .90% lysine and 2.72 g lysine/Mcal ME. Pigs previously fed with increasing lysine:calorie ratio had decreased (linear, P < .02) ADG and G:F. Also, pigs previously fed increasing CWG had decreased (linear, P < .03) ADG and ADFI. From 90.7 to 107 kg when all pigs were fed a diet containing .70% lysine and 2.1 g lysine/Mcal ME, growth performance was not affected by previous dietary treatment. Carcass characteristics were not affected by CWG or lysine:calorie ratio fed from 29.5 to 72.6 kg. Increasing the dietary energy density and lysine:calorie ratio improved ADG and G:F of growing pigs; however, pigs fed a low-energy diet or a low lysine:calorie ratio from 29 to 72 kg had compensatory growth from 72 to 90 kg.  相似文献   

9.
A total of 480 nursery pigs(Duroc×Landrace×Large White) were utilized in two experiments conducted to determine the effects of different ratios of standardized ileal digestible lysine(SIDLys)to metabolizable energy(ME)ratio on the performance,nutrient digestibility,plasma urea nitrogen (PUN),and plasma free anlino acids of 10 to 28 kg pigs.In Exp.1,192 pigs(10.58 kg)were assigned to one of four treatments.,The treaunents consisted of diets with a ME content of 3.2,3.25,3.3,or 3.35 McaL/kg with a constant SID-Lys:ME ratio of 3.7 g/Meal.The experiment lasted 28 days.Pigs which were fed the diets containing 3.3 and 3.35 Mcal/kg ME had lower feed intakes(P<0.05)than those fed 3.2 Mcal/kg.Feed efficiency was linearly improved with increasing dietary ME(P<0.05).Increasing the dietary ME level also increased (P<0.05)dry matter and energy digestibility.Therefore.3.3 Mcal/kg ME Was selected for Exp.2in which 288 pigs(10.60 kg)were assigned to one of six treatments.Treatments consisted of SID-Lys:ME ratios of 3.1,3.3,3.5,3.7,3.9,or 4.1 g/Meal witIl all diets providing 3.3 Meal of ME/kg.Weight gain and feed efficiency were increased(P<0.05)as the SID-Lys:ME ratio in diet increased.Based on a straight broken-line model,the estimated SID-Lys:ME ratio to maximize weight gain was 3.74.  相似文献   

10.
Crossbred barrows (n = 336 Newsham Hybrids) initially 9.9 kg and 31+/-2 d of age were used to evaluate the effects of energy density and lysine:calorie ratio on growth performance. Pigs were allotted by initial weight in a 3 x 4 factorial arrangement of treatments in a randomized complete block design with six replicate pens per treatment. Each pen had four or five pigs with an equal number of pigs per pen within replicate. Pigs were fed increasing dietary energy densities (3.25, 3.38, and 3.51 Mcal ME/kg) and lysine:calorie ratios (3.00, 3.45, 3.90, and 4.35 g lysine/Mcal ME). Energy density was changed by levels of choice white grease (0, 3, and 6%), and lysine:calorie ratio was changed by altering the corn:soybean meal ratio. Over the 21-d trial, an energy density x lysine:calorie ratio interaction was observed for ADG (P < .05). Pigs fed diets containing 3.25 or 3.51 Mcal ME/kg had increasing ADG with increasing lysine:calorie ratio, whereas ADG of pigs fed 3.38 Mcal ME/kg was not affected by lysine:calorie ratio. Feed efficiency (gain:feed ratio) increased and ADFI decreased as lysine:calorie ratio increased (linear, P < .01) and as energy density increased (quadratic, P < .01 and .10, respectively). On d 21, two pigs per pen were scanned ultrasonically for backfat depth. An energy density x lysine:calorie ratio interaction (P < .06) was observed. Pigs fed diets containing 3.25 and 3.38 Mcal ME/kg had decreasing fat depth as lysine:calorie ratio increased; however, backfat depth was not affected by lysine:calorie ratio and was greatest for pigs fed 3.51 Mcal ME/kg. These results suggest that 10- to 25-kg pigs fed diets containing 3.38 Mcal ME/kg had maximum feed efficiency and that they required at least 4.35 g lysine/Mcal ME. However, pigs fed 3.51 Mcal ME/kg had increased fat depth regardless of calorie:lysine ratio.  相似文献   

11.
Five experiments were conducted to determine if boars and barrows differ in the level of dietary lysine required to maximize growth rate, efficiency of feed utilization, carcass leanness and N retention. In Exp. 1, 48 boars and 48 barrows were fed fortified corn-soybean meal diets calculated to contain 14 (grower) and 12% protein (finisher) and supplemented with 0, .15 or .30% lysine from 27 to 105 kg body weight. The basal diets analyzed .60 and .47% lysine, respectively. Linear improvements in feed/gain (P less than .01), backfat thickness (P less than .10), longissimus muscle area (P less than .01), and ham-loin (P less than .05) and lean cuts percentage (P less than .1) were observed in boars as dietary lysine increased. In barrows, however, growth rate, feed:gain ratio and carcass characteristics (except longissimus muscle area) were not significantly affected by dietary lysine level. In Exp. 2, 18 boars and 18 barrows initially averaging 64 kg body weight were fed a 12% protein diet (.47% lysine) supplemented with 0, .15 or .30% lysine. Linear (P less than .05) increases in N retention occurred in boars, but not barrows, as dietary lysine was increased. In Exp. 3 and 4, 140 boars (34 to 103 kg) were fed a 14-12% protein sequence (analyzed .61 and .48% lysine) supplemented with 0, .1, .2, .3 or .4% lysine. In Exp. 5, 60 boars (23 to 103 kg) were fed a 16-14% protein sequence (analyzed .83 and .68% lysine) supplemented with 0, .075, .15 or .225% lysine.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

12.
Two experiments were conducted to evaluate the comparative feeding value of dried shredded sugarbeets (DSSB; 0, 20, and 40% of diet DM) as a replacement for steam-flaked corn (SFC) in finishing diets for feedlot cattle. In Exp. 1, 60 calf-fed Holstein steers (476 ± 6.3 kg) were used in a 97-d finishing trial. Substitution of SFC with DSSB did not affect ADG or DMI (P > 0.20). Increasing DSSB decreased gain efficiency (ADG:DMI; linear effect, P = 0.04) and dietary NE (linear effect, P = 0.03). Given that SFC has a NE(m) value of 2.38 Mcal/kg, the replacement NE(m) and NE(g) values for DSSB were 1.94 and 1.29 Mcal/kg, respectively. There were no treatment effects (P > 0.20) on carcass characteristics. In Exp. 2, 6 cannulated Holstein steers (205 kg) were used in a replicated 3 × 3 Latin square design to evaluate treatment effects on digestion. Ruminal digestion of starch, NDF, and feed N were not affected (P > 0.10) by DSSB, although ruminal OM digestion tended to increase (linear effect, P < 0.08). Replacing SFC with DSSB decreased flow of starch to the small intestine, but it increased flow of microbial N (linear effect, P = 0.05). There were no treatment effects (P > 0.14) on postruminal digestion of OM, NDF, starch, or feed N or total tract digestion of OM, starch, and N. Substitution of DSSB increased (linear effect, P = 0.05) total tract NDF digestion and decreased (linear effect, P = 0.05) dietary DE (Mcal/kg). Given that SFC has a DE value of 4.19 Mcal/kg, the replacement DE value of DSSB was 3.68 Mcal/kg. There were no treatment effects (P > 0.12) on ruminal pH or total VFA; however, DSSB decreased propionate (linear effect, P = 0.05) and increased acetate (linear effect, P = 0.07), butyrate (linear effect, P = 0.05), valerate (linear effect, P = 0.04), and estimated methane production (linear effect, P = 0.05). We concluded that DSSB may replace SFC in finishing diets at levels of up to 40% without detrimental effects on ADG and carcass characteristics. The NE value of DSSB is 82% that of SFC (DM basis). Partial replacement of SFC with DSSB alters ruminal VFA patterns, increasing estimated methane energy loss and slightly decreasing the efficiency of DE utilization.  相似文献   

13.
Seventy-two crossbred (Large White X Landrace) pigs were used in a 3 X 7 factorial experiment to investigate the response of two strains of boars (strains A and B) and of castrated male pigs (strain B) to seven levels of intake of a single diet (ranging from 5.3 Mcal digestible energy [DE]/d to ad libitum) between 45 and 90 kg live weight. All aspects of growth performance and body composition were affected to different degrees by both strain and sex. At all levels of energy intake strain A boars grew faster, had a lower feed to gain ratio and contained less fat and more water in the empty body than strain B boars, which in turn exhibited faster live weight gain and more efficient and leaner growth than castrated males. The magnitude of the differences in growth performance between strain A and strain B boars and castrates increased with increased energy intake above 7.88 Mcal DE/d, and these differences were associated with concomitant strain differences in their respective capacity for protein growth and in the relationship between energy intake and protein deposition. For strain A boars the rate of protein deposition increased linearly from 92 to 188 g/d with increased energy intake from 5.3 Mcal DE/d to ad libitum. For strain B boars and castrates the rate of protein deposition increased linearly with increased energy intake up to 7.88 Mcal DE/d, but thereafter it remained constant at 128 and 85 g/d, respectively. For castrates protein deposition was depressed (P less than .01) when the diet was offered ad libitum. Strain A boars had a higher energy requirement for maintenance (3.55 Mcal DE/d) than strain B boars (2.77 Mcal DE/d) or castrates (2.60 Mcal DE/d). Strain A boars also contained less protein and more water in the fat free empty body than the other two pig types.  相似文献   

14.
Digestible lysine requirement of starter and grower pigs   总被引：1，自引：0，他引：1  
Three experiments were conducted to determine the digestible lysine requirement of starter (6 kg BW initially) and of grower (21 kg BW initially) pigs. Experiment 1 used 294 starter pigs and lasted 28 d; Exp. 2 used 182 grower pigs and lasted 35 d. Protein and total lysine contents of the basal corn-peanut meal diets were 20 and .8% for Exp. 1 and 16 and .54% for Exp. 2. Basal diets were fortified with five incremental additions of lysine.HCl to provide lysine contents ranging from .8 to 1.3% in Exp. 1, and .54 to .94% in Exp. 2. Diets contained crystalline tryptophan, threonine and isoleucine (Exp. 1 only) to provide dietary concentrations equal to 18, 70 and 60% of the highest lysine level fed. Average daily gain and gain/feed of both starter and grower pigs increased (P less than .05) linearly and quadratically as dietary lysine level increased. For starter pigs, ADG and gain/feed were optimized at 1.1 to 1.2% total lysine. For grower pigs, ADG and gain/feed were optimized at .86% total lysine. In Exp. 3, barrows fitted with an ileal T-cannula were used in a 4 X 4 Latin square design. Basal diets and diets with added lysine were evaluated. Apparent lysine digestibility of the basal starter and grower diets and lysine.HCl were 79.9, 74.1 and 96.7%, respectively. Based on these values and the total lysine contents found to optimize performance, the digestible lysine requirements of starter and grower pigs are 1.03 and .71%, respectively.  相似文献   

15.
A total of 2,121 growing-finishing pigs (Duroc × Landrace × Large White) were utilized in six experiments conducted to determine the effects of different ratios of standardized ileal digestible lysine (SID-Lys) to metabolizable energy (ME) on the performance and carcass characteristics of growing-finishing pigs. Exps. 1 (30 to 50 kg), 2 (52 to 70 kg) and 3 (81 to 104 kg) were conducted to find an optimum ME level and then this level was used in Exps. 4 (29 to 47 kg), 5 (54 to 76 kg) and 6 (84 to 109 kg) to test the response of pigs to different ratios of SID-Lys:ME. In Exps.1 to 3, four treatments were used consisting of diets with a formulated ME content of 3.1, 3.2, 3.3 or 3.4 in Exps. 1 and 2 while Exp. 3 used 3.05, 3.15, 3.25 or 3.35 Mcal/kg. A constant SID-Lys:ME ratio of 2.6, 2.3 or 2.0 g/Mcal was used in Exps. 1, 2 and 3, respectively. Weight gain was significantly increased with increasing energy level in Exp.1 while weight gain was unaltered in Exps. 2 and 3. For all three experiments, feed intake was decreased (P < 0.05) and feed efficiency was improved (P < 0.05) with increasing energy level. Tenth rib back fat thickness linearly increased (P < 0.05) with increasing energy level. In Exps. 4 to 6, five treatments were used consisting of diets with a SID-Lys:ME ratio of 2.4, 2.6, 2.8, 3.0 or 3.2 in Exp. 1, 2.1, 2.3, 2.5, 2.7, 2.9 or 3.2 in Exp. 2 and 1.8, 2.0, 2.2, 2.4, or 2.6 in Exp. 3. A constant ME level 3.2, 3.2 and 3.05 Mcal/kg was used in Exps. 1, 2 and 3, respectively (selected based on the results of weight gain). For all three experiments, weight gain increased (P < 0.05) and feed efficiency improved linearly (P < 0.05) as the SID-Lys:ME ratio increased. Tenth rib back fat thickness linearly decreased (P < 0.05) as the SID-Lys:ME ratio increased. Based on a straight broken-line model, the estimated SID-Lys:ME ratio to maximize weight gain was 3.0, 2.43 and 2.2 for 29 to 47, 54 to76 and 84 to 109 kg of pigs, respectively.  相似文献   

16.
1. The aim of the study was to examine the response of male broilers of different age categories to different dietary ideal protein (IP) concentrations and to compare the effects to IP recommendations based on single lysine (Lys) requirement studies from the literature. 2. Two experiments were carried out, in which diets containing different IP concentrations (9.0 to 14.4g apparent faecal digestible (AFD) Lys/kg) were fed to male broilers from 14 to 34 (Exp. 1) and 28 to 41 d of age (Exp. 2). The diets (12.88MJ AMEN/kg) were prepared by the dilution technique. The effect of dietary IP concentrations on weight gain, feed intake, feed conversion efficiency (FCE) and slaughter characteristics were studied in both experiments. 3. In Exp. 1, weight gain and FCE increased linearly and fat concentration in the carcase decreased with increasing IP concentration. In Exp. 2, weight gain and FCE improved exponentially, whereas breast meat yield improved linearly with increasing dietary IP concentration. On the basis of these results, it was concluded that the weight gain and FCE of male broilers respond to higher dietary IP levels than would be expected from single lysine requirement studies in the literature.  相似文献   

17.
Three digestion experiments and one growth experiment were conducted to determine site, extent and ruminal rate of forage digestion and rate and efficiency of gain by cattle offered alfalfa haylage supplemented with corn or dry corn gluten feed (CGF). In Exp. 1, eight steers were fed alfalfa haylage-based diets with substitution of corn for 0, 20, 40 or 60% of haylage in a 4 X 4 latin square. Increasing dietary corn substitution increased (P less than .05) OM, NDF and ADF digestion by steers but decreased (P less than .05) rate of in situ alfalfa DM digestion. In Exp. 2, five heifers were fed alfalfa haylage-based diets with increasing dietary levels of CGF in a 5 X 5 latin square. Increasing dietary CGF increased (P less than .05) OM, NDF and ADF digestion by heifers. In Exp. 3 and 4, cattle were fed alfalfa haylage-based diets containing either 20 or 60% corn or CGF. In Exp. 3, supplementation increased (P less than .05) OM and NDF digestion but level X supplement source interaction (P less than .05) occurred, with added CGF increasing OM and NDF digestion more than added corn. In Exp. 4, supplementation improved (P less than .05) DM intake, daily gain and feed efficiency. Dry matter intake and daily gain were greater (P less than .05) for 60% supplementation than for 20% supplementation. Overall, whereas increasing the level of dietary supplement increased (P less than .05) OM, NDF and ADF digestion, only corn addition decreased (P less than .05) rate of in situ alfalfa DM digestion. Daily gains and feed efficiencies were similar in cattle fed either corn or CGF with alfalfa haylage.  相似文献   

18.
Two trials were conducted to determine the NE value of ensiled wet corn gluten feed (WCGF) in corn silage finishing diets for beef cattle. In Trial 1, 96 Angus-crossbred yearling steers were fed corn silage-based diets containing 0, 20, 40, or 60% ensiled WCGF. Increased dietary WCGF resulted in improved DMI (linear, P less than .05), ADG (linear; P less than .05), and feed/gain (linear, P less than .05). Levels of WCGF had no (P greater than .05) effect on fat thickness, marbling, quality grade, carcass protein, and carcass fat. In Trial 2, four Angus-crossbred yearling steers were used in a 4 x 4 Latin square design to determine the effect of feeding 0, 20, 40, or 60% WCGF on DE and ME values. Level of WCGF had no (P greater than .05) effect on dietary DE and ME values. Regression equations were developed for predicting NEm (Y = 1.51 + .0009X; R2 = .22) and NEg (Y = 1.04 + .0028X; R2 = .35) in which Y = predicted diet NE values in megacalories/kilogram and X = percentage of dietary WCGF. The NEg value increased .06 Mcal/kg for each 20% increase in WCGF. Predicted NEm and NEg values for WCGF are 1.60 and 1.32 Mcal/kg, respectively.  相似文献   

19.
Sixty sows were individually penned in a thermoneutral (20 degrees C) or hyperthermal (32 degrees C) environment and fed a basal (corn-soybean meal), high-fiber (48.5% wheat bran) or high-fat (10.6% choice white grease) diet from d 100 of gestation through a 22-d lactation. The diets were determined to contain 3.28, 2.76 and 3.75 Mcal ME/kg, respectively. All pigs received 8.0 Mcal of ME and 17.5 g of lysine daily prior to parturition and were allowed to consume their respective diets ad libitum after parturition. Litter size was standardized at 9 to 10 pigs by d 2 postpartum. Milk yields were determined for five, 4-d periods from about d 2 through 22 of lactation via a D2O dilution technique. Daily milk yield and litter weight gain began to plateau, and the efficiency of utilizing milk DM and milk energy for gain was depressed (P less than .01), in the latter stages of the lactation. Heat exposure (32 degrees C) reduced (P less than .05) voluntary ME intake and milk energy yield of the sow and increased (P less than .05) the sow's weight loss during lactation. In the hot environment, increasing dietary energy concentration resulted in a linear (P less than .08) increase in milk fat content and milk energy yield over the duration of the 22-d lactation. In the latter stages of lactation, pigs consuming high-fat milk required more (P less than .09) milk and milk energy per unit of weight gain. In the warm environment, milk energy yield was increased by dietary fat or fiber additions in early lactation, but not in late lactation. These results indicate that the effects of thermal heat stress on sow milk energy yield and litter weight gain are aggravated by dietary fiber addition and minimized by dietary fat addition.  相似文献   

20.
Eighteen weanling horses were assigned to two treatments: limited or ad libitum feed intake. Growth and feed utilization were evaluated over a 78-wk period. Ad libitum-fed horses gained 24% more (P less than .05) weight than limit-fed horses. Total BW was distributed into 57% fore and 43% hind weight and did not differ between groups regardless of dietary treatment or age. Net gain and ADG in wither height of ad libitum-fed horses exceeded (P less than .05) that of limit-fed horses over 78 wk. Ad libitum-fed horses consumed 19, 44 and 34% more digestible energy (DE) than indicated in 1978 NRC tables from 6 to 12 mo, 12 to 18 mo and 18 to 24 mo of age, respectively. Total DE intakes were positively correlated to weight and therefore were confounded by age. Weight-scaled DE intake of ad libitum-fed weanling horses increased .2% for each 1 C degree decrease in barn temperature below 0 degree C. Maintenance energy requirements were estimated at 37.8 and 35.6 kcal DE/kg BW for limit- and ad libitum-fed horses, respectively. Grams of gain per megacalorie of DE consumed above maintenance ranged from 83 to 24 g/Mcal and were only 22 to 75% of values derived from 1978 NRC tables. Energy guidelines given by NRC were considered suitable for growth based on normalcy of musculoskeletal growth. However, the ADG by our horses, which were fed high-forage diets, were lower than those predicted by 1978 NRC.  相似文献   

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