Prediction of net energy value of feeds for growing pigs

Determination of the net energy content of canola meal from Brassica napus yellow and Brassica juncea yellow fed to growing pigs using indirect calorimetry

The net energy (NE) content of canola meals (CM; i.e. Brassica napus yellow and Brassica juncea yellow) in growing pigs was determined using an indirect calorimetry chamber or published prediction equations. The study was conducted as a completely randomized design (n=6), with (i) a basal diet and (ii) 2 diets containing 700 g/kg of the basal diet and 300 g/kg of either of the two varieties of CM. A total of 18 growing barrows were housed in metabolism crates for the determination of digestible (DE) and metabolizable (ME) energy. Thereafter, pigs were transferred to the indirect calorimetry chamber to determine heat production (HP). The NE contents of diets containing Brassica napus yellow and Brassica juncea yellow determined with the direct determination technique and prediction equations were 9.8 versus 10.3 MJ/kg dry matter (DM) and 10.2 versus 10.4 MJ/kg DM, respectively. Retained energy (RE) and fasting heat production (FHP) of diets containing Brassica napus yellow and Brassica juncea yellow were 5.5 versus 5.7 MJ/kg and 4.3 versus 4.5 MJ/kg, respectively, when measured with the direct determination technique and prediction equations. The NE contents of Brassica napus yellow and Brassica juncea yellow were determined to be 8.8 and 9.8 MJ/kg DM, respectively, using the direct determination technique.

Effects of dietary soybean oil on pig growth performance, retention of protein, lipids, and energy, and the net energy of corn in diets fed to growing or finishing pigs

The objectives of this experiment were 1) to determine if dietary soybean oil (SBO) affects the NE of corn when fed to growing or finishing pigs, 2) to determine if possible effects of dietary SBO on the NE of corn differ between growing and finishing pigs, and 3) to determine effects of SBO on pig growth performance and retention of energy, protein, and lipids. Forty-eight growing (initial BW: 27.3 ± 2.5 kg) and 48 finishing (initial BW: 86.0 ± 3.0 kg) barrows were used, and within each stage of growth, pigs were allotted to 1 of 6 groups. Two groups at each stage of growth served as an initial slaughter group. The remaining 4 groups were randomly assigned to 4 dietary treatments and pigs in these groups were harvested at the conclusion of the experiment. A low-lipid basal diet containing corn, soybean meal, and no added SBO and a high-lipid basal diet containing corn, soybean meal, and 8% SBO were formulated at each stage of growth. Two additional diets at each stage of growth were formulated by mixing 25% corn and 75% of the low-lipid basal diet or 25% corn and 75% of the high-lipid basal diet. Results indicated that addition of SBO had no effects on growth performance, carcass composition, or retention of energy, protein, and lipids but increased (P < 0.05) apparent total tract digestibility of acid hydrolyzed ether extract and GE. Addition of SBO also increased (P < 0.05) DE and NE of diets, but had no effect on the DE and NE of corn. Finishing pigs had greater (P < 0.05) growth performance and retention of energy, protein, and lipids than growing pigs. A greater (P < 0.05) DE and NE of diets was observed for finishing pigs than for growing pigs and the DE and NE of corn was also greater (P < 0.05) for finishing pigs than for growing pigs. In conclusion, addition of SBO increases the DE and NE of diets but has no impact on the DE and NE of corn. Diets fed to finishing pigs have greater DE and NE values than diets fed to growing pigs and the DE and NE of corn are greater for finishing pigs than for growing pigs.

Effects of reduced-oil corn distillers dried grains with solubles composition on digestible and metabolizable energy value and prediction in growing pigs

Two experiments were conducted to determine the DE and ME content of corn distillers dried grains with solubles (corn-DDGS) containing variable ether extract (EE) concentrations and to develop DE and ME prediction equations based on chemical composition. Ether extract content of corn-DDGS ranged from 4.88 to 10.88% (DM basis) among 4 corn-DDGS samples in Exp. 1 and from 8.56 to 13.23% (DM basis) among 11 corn-DDGS samples in Exp. 2. The difference in concentration of total dietary fiber (TDF) and NDF among the 4 corn-DDGS sources was 2.25 and 3.40 percentage units, respectively, in Exp. 1 but was greater among the 11 corn-DDGS sources evaluated in Exp. 2, where they differed by 6.46 and 15.18 percentage units, respectively. The range in CP and ash were from 28.97 to 31.19% and 5.37 to 6.14%, respectively, in Exp. 1 and from 27.69 to 32.93% and 4.32 to 5.31%, respectively, in Exp. 2. Gross energy content among corn-DDGS samples varied from 4,780 to 5,113 kcal/kg DM in Exp. 1 and from 4,897 to 5,167 kcal/kg DM in Exp. 2. In Exp. 1, the range in DE content was from 3,500 to 3,870 kcal/kg DM and ME content varied from 3,266 to 3,696 kcal/kg DM. There were no differences in ME:DE content among the 4 corn-DDGS sources in Exp. 1, but ME:GE content differed (P = 0.04) among sources (66.82 to 74.56%). In Exp. 2, the range in DE content among the 11 corn-DDGS sources was from 3,474 to 3,807 kcal/kg DM and ME content varied from 3,277 to 3,603 kcal/kg DM. However, there were no differences in DE:GE, ME:DE, or ME:GE among sources in Exp. 2. In Exp. 1, no ingredient physical or chemical measurement [bulk density (BD), particle size, GE, CP, starch, TDF, NDF, ADF, hemicellulose, EE, or ash)] was statistically significant at P ≤ 0.15 to predict DE or ME content in corn-DDGS. In Exp. 2, the best fit DE equation was DE (kcal/kg DM) = 1,601 - (54.48 × % TDF) + (0.69 × % GE) + (731.5 × BD) [R(2) = 0.91, SE = 41.25]. The best fit ME equation was ME (kcal/kg DM) = 4,558 + (52.26 × % EE) - (50.08 × % TDF) [R(2) = 0.85, SE = 48.74]. Apparent total tract digestibility of several nutritional components such as ADF, EE, and N were quite variable among corn-DDGS sources in both experiments. These results indicate that although EE may be a good predictor of GE content in corn-DDGS, it is not a primary factor for predicting DE or ME content. Measures of dietary fiber, such as ADF or TDF, are more important than EE in determining the DE or ME content of corn-DDGS for growing pigs.

Banana meal for feeding pigs: digestive utilization, growth performance and feeding behavior

The main objective of the present work was to determine the nutritional value and the strategies of using green banana meal (BM) in growing pigs. Two trials involving a total of 96 growing pigs were designed to study the effect of the harvest stage on the nutritional and energy values of BM (trial 1) and to evaluate the consequence of feeding gradual levels of BM on growth performance and feeding behavior in growing pigs (trial 2). In trial 1, the digestive utilization of three diets including 40% BM were compared with a control (C) soybean meal-corn diet in two batches of 12 pigs. BM was obtained from fruits harvested at 750 degrees-days (DD; early harvesting stage), 900 DD (normal harvesting stage) and 1150 DD (late harvesting stage). In trial 2, 72 Large White pigs were grouped in pens of nine animals and were given ad libitum access to one of the four dietary treatments (two pens/diet) differing from the rate of inclusion of 900 DD BM (0%, 20%, 40%, 60%). The estimated energy apparent digestibility coefficients of BM increased with the harvest stage (75.5%, 80.7% and 83.2% for BM at 750, 900 and 1150 DD, respectively). Digestible energy and metabolizable energy values were higher for BM at 1150 DD (13.56 and 13.05 MJ/kg DM, respectively) than at 900 DD (13.11 and 12.75 MJ/kg DM, respectively) or at 750 DD (12.00 and 11.75 MJ/kg DM, respectively). In trial 2, average daily gain and feed conversion ratio were not affected (P>0.05) by the rate of BM inclusion (822 g/day and 2.75 kg/kg on average, respectively). Feed intake and feeding behavior parameters were not significantly influenced by the dietary treatments except for the rate of feed ingestion with a lower value for the diet with 40% of BM (27.4 v. 32.2 g/min on average; P<0.01) when compared with the other diets. Results of this study indicate that the energy value of BM increases with the harvest stage and that BM can be incorporated up to 60% in growing finishing pig diets.

Nonruminant Nutrition Symposium: Controlling feed cost by including alternative ingredients into pig diets: a review

Sustained price increases for traditional cereal grain and protein meal feed commodities have forced the pork industry to consider the dietary inclusion of alternative feedstuffs. Crop seed may serve as feedstuffs but their demand as feedstock for human food, biofuel, and bioindustrial products has increased. Together with these products, coproducts such as distillers dried grains with solubles, wheat millrun, and canola meal are produced. As omnivores, pigs are ideally suited to convert these non-human-edible coproducts into high-quality food animal protein. Therefore, coproducts and other low-cost alternative feedstuffs such as pulses and oilseeds can be included in pig diets to reduce feed cost per metric ton of feed. However, inclusion of alternative feedstuffs in pig diets does not necessarily reduce feed cost per kilogram of gain. Therefore, the use of novel and existing feedstuffs in pig diets must be optimized following their characterization for energy and AA profile. Alternative feedstuffs generally have a high content of at least 1 of the following antinutritional factors (ANF): fiber, tannins, glucosinolates, and heat-labile trypsin inhibitors. Several methods can optimize nutrient use of pigs fed alternative feedstuffs by reducing effects of their ANF. These methods include 1) particle size reduction to increase nutrient digestibility, 2) dehulling or scarification to reduce tannin and fiber content of pulses and oilseeds, 3) air classification to create fractions that have a greater content of nutrients and lower content of ANF than the feedstock, 4) heat treatments such as extrusion, toasting, roasting, and micronization to reduce heat-labile ANF, 5) dietary supplementation with fiber-degrading enzymes or predigestion of fibrous feedstuffs or diets with fiber-degrading enzymes to increase dietary nutrient availability, and 6) formulation of diets based on bioavailable AA coefficients. In conclusion, the feeding of alternative ingredients may reduce feed cost per unit of pork produced provided that their price per unit NE or digestible lysine is less than that of the traditional feedstuffs and that negative effects of their ANF are controlled.

Nutrient digestibility of lentil and regular- and low-oligosaccharide, micronized full-fat soybean fed to grower pigs

A study was conducted to determine the standardized ileal digestibility (SID) of AA and calculate the NE value for regular-oligosaccharide, micronized full-fat soybean (R-MFFSB), low-oligosaccharide, micronized full-fat soybean (LO-MFFSB), lentil, and enzymatically hydrolyzed casein (EHC) for growing pigs. Six ileal-cannulated barrows (31.4 kg BW) were fed 6 diets in a 6 × 6 Latin square. Five diets were cornstarch based, containing either soybean meal (SBM), R-MFFSB, LO-MFFSB, or EHC as sole protein source or N free. The sixth diet contained lentil as sole protein and energy source. The SID of AA for diets was calculated using the N-free diet. Digestibility of AA in feedstuffs was determined by the direct method. Energy digestibility in SBM, R-MFFSB, and LO-MFFSB was determined by difference from the N-free diet whereas energy digestibility in lentil was determined by the direct method. On DM basis, SBM, R-MFFSB, LO-MFFSB, and lentil contained 52, 43, 43, and 27% CP, 8, 12, 14, and 16% NDF, and 1.8, 19, 21, and 1.6% ether extract, respectively. The SID of Lys for SBM was greater (P < 0.05) than that for R-MFFSB or LO-MFFSB (76 vs. 79 and 79%). The SID of other indispensable AA (except Trp) for SBM was also greater (P < 0.05) than that for R-MFFSB or LO-MFFSB. The R-MFFSB and LO-MFFSB were similar in SID of AA. The SID of Lys for lentil (81%) was lower (P < 0.05) than that for SBM with a similar trend for SID of other indispensable AA except for Met and Thr whose SID was similar to SBM. The SID of AA for EHC ranged from 98 to 112%. The SBM had a lower (P < 0.05) NE value than R-MFFSB or LO-MFFSB (2.63 vs. 2.95 and 3.00 Mcal/kg DM). Lentil and SBM were similar in NE value (2.60 vs. 2.63 Mcal/kg DM). In conclusion, R-MFFSB and LO-MFFSB were similar in energy and AA value for pigs. Lentil had lower SID of AA than SBM. However, lentil and SBM were similar in NE value; therefore, lentil can serve as alternative pulse feedstuff for pigs. The AA in EHC were mostly completely digested indicating that EHC can be fed to estimate ileal endogenous AA losses.

Digestibility and metabolic utilization of diets containing whole-ear corn silage and their effects on growth and slaughter traits of heavy pigs

The aim was to evaluate 2 levels of dietary inclusion of chopped whole-ear corn silage (WECS) on energy and nutrient utilization, growth, and slaughter performances of heavy pigs. Two in vivo experiments were conducted to determine digestibility and metabolic utilization of WECS using 18 barrows weighing 118 ± 8 kg BW on average, metabolic cages and respiration chambers (Exp. 1), and the effect of WECS on the growth performance and carcass traits on 42 barrows from 90 to 170 kg BW (Exp. 2). In both experiments, pigs were fed 3 experimental diets: a control diet (CON) containing cereal meals, extracted soybean meal, and wheat bran (80%, 9%, and 8% of DM, respectively) and 2 diets containing 15% (15WECS) or 30% WECS (30WECS) on a DM basis in place of wheat bran and corn meal. The diets were prepared daily by mixing the WECS to a suitable compound feed. Feed intake was always restricted to allow a daily DMI of 7.2% BW(0.75) in Exp. 1 and from 8.0% to 6.5% BW(0.75) in Exp. 2. Diets had similar NDF contents (15.2% to 15.8% of DM), and WECS inclusion resulted in a slight reduction in CP content (from 14.0% to 13.6% of DM) and a considerable decrease in P content (from 0.47% to 0.30% of DM). Digestibility of OM, CP, and fat was similar among diets, whereas P digestibility was lower (P < 0.05) for the 30WECS diet (33.5%) in comparison with the CON and 15WECS diets (45.5% and 44.1%, respectively). Nitrogen lost in feces and urine and N retained were not different among diets, whereas P retained decreased with the increase of WECS (5.4, 3.7, and 2.2 g/d for the CON, 15WECS, and 30WECS diets, respectively; P < 0.05). No difference among diets was observed for energy balance. The WECS contained 13.48 MJ ME and 9.39 MJ NE/kg DM. In Exp. 2, feed intake was not depressed by WECS inclusion, and the ADG for the whole experiment was not different among dietary treatments (from 737 to 774 g/d). Fecal pH was lower (P < 0.05) for the WECS diets than the control diet (7.10 and 7.00 vs. 7.40) and for the sampling at 150 kg BW than that at 130 and 110 kg BW (6.96 vs. 7.29 and 7.24). At slaughter, lean percentage in the carcass was lower in the 30WECS diet than those of the other 2 diets (46.8% vs. 48.3% and 48.6%, P = 0.05). The overall experimental data obtained in both trials indicate that substitution of wheat bran and corn meal for WECS (up to 30% of DM) does not affect, with the exception of P utilization and carcass leanness, energy and nutrient utilization and performance of heavy pigs in the last phase of growing.

Effect of insoluble-low fermentable fiber from corn-ethanol distillation origin on energy, fiber, and amino acid digestibility, hindgut degradability of fiber, and growth performance of pigs

Extensive use of corn coproducts in swine diets increases the concentration of dietary fiber, raising concerns on energy and nutrient digestibility and, ultimately, pig performance. A digestion trial was conducted to determine the effect of increasing levels of insoluble-low fermentable fiber from corn in the diet, using corn bran with solubles (CBS) from the corn-ethanol distillation industry, on digestibility of energy, fiber, and AA, and hindgut fermentation of fiber in diets fed to growing pigs. Fifteen growing pigs (BW=28.7 kg) arranged in a 3-period incomplete block design and fitted with a T-cannula in the distal ileum were provided 5 diets (n=9) containing either a corn-casein basal or the basal diet with 10, 20, 30, or 40% CBS. Fecal and ileal digesta samples were collected. Two subsequent 28-d growth trials determined the effects of increasing dietary fiber from CBS in 2 sets of 7 diets formulated either with declining (growing phase: 2,387 to 2,133 kcal NE/kg; finishing phase: 2,499 to 2,209 kcal NE/kg) or constant dietary NE (growing phase≈2,390 kcal NE/kg; finishing phase≈2,500 kcal NE/kg) on growth performance and apparent total tract digestibility (ATTD) of energy in 70 growing (BW=48.9 kg; n=10 per diet) and 70 finishing (BW=102.0 kg; n=10) pigs. Results indicated that increasing fiber from corn lowered (P<0.01) the apparent ileal digestibility of all indispensable amino acids except Arg, GE, DM, and CP but not NDF or total dietary fiber (TDF). Increased fiber from corn also reduced ATTD of GE, DM, CP, NDF, and TDF (P<0.01). Increasing fiber with declining diet NE lowered BW, ADG, and G:F (P<0.05) in growing and in finishing pigs. When NE was held constant, as fiber increased, BW and ADG were unaffected in growing and finishing pigs, and G:F was unaffected in finishing pigs but improved in growing pigs (P<0.05) with increasing dietary fiber. In both growing and finishing pigs, ADFI was unaffected by the increased fiber from corn, regardless of the NE content of diets. In conclusion, the dietary level of insoluble-low fermentable dietary fiber from corn origin decreased the digestibility of dietary AA, and the ability of the growing pig to ferment corn dietary fiber. In spite of the reduction in digestibility of energy and nutrients with insoluble-low fermentable fiber level from corn, growth performance was not impaired when the energy supply is adequately balanced in the diet using the NE system.

Microencapsulated lysine and low-protein diets: effects on performance, carcass characteristics and nitrogen excretion in heavy growing-finishing pigs

Two studies were conducted to assess the effects of dietary protein and Lys reduction on growth performance, carcass quality, N excretion, and plasma N profile in growing-finishing pigs from 35 to 180 kg. The growing trial was conducted with 72 gilts and 72 barrows with 6 pens per treatment and 6 gilts or 6 barrows per pen. Four diets with the same DE and NE were compared: 1) control diet, 2) diet with protein content reduced by 3% units compared with the control diet and supplemented with Lys HCl to match the requirements according to the 2012 NRC (FLys), 3) diet similar to FLys for protein level but supplemented with only 50% of the Lys HCl provided with FLys (-50% FLys), and 4) diet similar to FLys and -50% Flys for protein level with microencapsulated Lys added to supply 20% of the Lys provided by FLys (-80% MLys). Pigs fed the FLys diet performed in a similar manner and showed similar carcass characteristics to the control pigs. Pigs fed the -50% FLys diet had the lightest BW (P < 0.01) as well as the lightest carcass (P = 0.02) and trimmed thigh (P = 0.04) weights. Pigs fed the -80% MLys diet showed growth performance and carcass characteristics similar to the control pigs. The N balance study was conducted with 8 barrows arranged in a double replicated 4 × 4 Latin square design. The control pigs had greater (P < 0.01) N intake and urinary and total N excretion compared with pigs fed the low-protein diets. The reduction of the dietary protein concentration by 3% units decreased total N excretion by an average of 24.5% and the greatest reduction of total N excretion was obtained by the -80% MLys diet (26.12%) compared with the control diet throughout the trial. No effect of dietary treatment was observed on the plasma concentrations of ammonia, urea, and total AA in the 80-kg pigs. Decreased plasma ammonia (P < 0.01) and urea (P = 0.03) concentrations were detected in the 120-kg pigs fed the low-protein diets. The 160-kg pigs fed the -80% MLys pigs had less total AA, indispensable AA in particular (P < 0.01), than pigs fed the other diets and decreased ammonia (P < 0.01) and urea (P = 0.05) concentrations than the control pigs. The results showed that the use of microencapsulated Lys, compared with both Lys HCl and dietary protein-bound Lys, can save CP and synthetic AA in diet formulation and can reduce N excretion in manure without adversely affecting the growth performance and carcass quality of heavy growing-finishing pigs.

Response of piglets to the standardized ileal digestible isoleucine, histidine and leucine supply in cereal-soybean meal-based diets

Improving the amino acid (AA) profile of the diet by using l-Lys, l-Thr, dl-Met, l-Trp and l-Val helps to reduce the dietary CP content, thereby reducing nitrogen excretion while maintaining the performance of pigs. Valine is the fifth limiting AA in cereal-soybean meal-based diets. The extent to which the CP content in the diet can be reduced further without compromising performance depends on the requirement of the next limiting AA. In cereal-soybean meal-based diets, Ile, His and Leu may be the limiting AAs after Val, although information on the requirements for these AAs is scarce. Six experiments were conducted to determine the effect of supplementing a low-CP diet with l-Ile, l-His and l-Leu on the performance of pigs weighing 10 to 20 kg. Experiment 1 was designed to determine the most limiting AA with respect to performance among Ile, His and Leu. A diet 10% deficient in Ile, Leu and His relative to the National Research Council (NRC, 1998) requirement estimates tended to decrease daily feed intake and daily gain by 6% and 8%, respectively. A 10% deficiency in His alone had no effect, whereas a 10% deficiency in Ile or Leu slightly reduced daily feed intake and gain. In the remaining experiments, the standardized ileal digestible (SID) Ile : Lys, His : Lys and Leu : Lys requirements were estimated. In Experiments 2, 3, 4, 5 and 6, 14 blocks of six pigs each were assigned to six levels of SID Ile : Lys (40%, 43%, 46%, 49%, 52% and 55%), His : Lys (20%, 24%, 28%, 32%, 36% and 40%), His : Lys (21%, 24%, 27%, 30%, 33% and 36%), Leu : Lys (70%, 78%, 86%, 94%, 102% and 110%) and Leu : Lys (80%, 90%, 100%, 110%, 120% and 130%), respectively. Across experiments, the estimated SID Ile : Lys, His : Lys and Leu : Lys requirements for maximizing daily gain were 49%, 32% and 102%, respectively, using a curvilinear plateau model. When Ile, His and Leu levels were 10% below the requirement estimate, daily gain was reduced by 9%, 3% and 3%, respectively. The results of this study indicate that the Ile requirement estimate is lower than the current NRC requirement estimate, whereas the Leu and His requirements correspond to those proposed by the NRC.

Effects of dietary soybean hulls and wheat middlings on body composition, nutrient and energy retention, and the net energy of diets and ingredients fed to growing and finishing pigs

The objectives of this experiment were 1) to determine the effect of dietary soybean hulls (SBH) and wheat middlings (WM) on body composition, nutrient and energy retention, and the NE of diets and ingredients fed to growing or finishing pigs and 2) to determine if finishing pigs use the energy in SBH and WM more efficiently than growing pigs. Forty growing barrows (initial BW: 25.4 ± 0.7 kg) and 40 finishing barrows (initial BW: 84.8 ± 0.9 kg) were randomly allotted to 5 groups within each stage of growth. Two groups at each stage of growth served as the initial slaughter group. The remaining pigs were randomly assigned to 3 dietary treatments and harvested at the conclusion of the experiment. The basal diet was based on corn and soybean meal and was formulated to be adequate in all nutrients. Two additional diets were formulated by mixing 70% of the basal diet and 30% SBH or 30% WM. In the growing phase, ADG, G:F, and retention of lipids were greater (P < 0.05) for pigs fed the basal diet than for pigs fed the diets containing SBH or WM. Retention of energy was also greater (P < 0.05) for pigs fed the basal diet than for pigs fed the SBH. In the finishing phase, pigs fed the SBH diet tended (P = 0.10) to have a greater ADG than pigs fed the WM diet, and energy retention was greater (P < 0.05) for pigs fed the basal diet than for pigs fed the WM diet. The NE of the basal diet fed to growing pigs was greater (P < 0.01) than the NE of the diets containing SBH or WM, and there was a tendency for a greater (P = 0.05) NE of the basal diet than of the other diets when fed to finishing pigs. The NE of SBH did not differ from the NE of WM in either growing or finishing pigs, and there was no interaction between ingredients and stage of growth on the NE of diets or ingredients. The NE of diets for growing pigs (1,668 kcal/kg) was not different from the NE of diets for finishing pigs (1,823 kcal/kg), and the NE of the diets containing SBH (1,688 kcal/kg) was not different from the NE of the diets containing WM (1,803 kcal/kg). Likewise, the NE of SBH (603 kcal/kg) did not differ from the NE of WM (987 kcal/kg). In conclusion, inclusion of 30% SBH or WM decreases the performance and nutrient retention in growing pigs but has little impact on finishing pigs. The NE of the diets decreases with the inclusion of SBH and WM, but the NE of diets and ingredients is not affected by the BW of pigs. The NE of SBH is not different from the NE of WM.

Strategies to improve fiber utilization in swine

Application of feed processing methods and use of exogenous feed additives in an effort to improve nutrient digestibility of plant-based feed ingredients for swine has been studied for decades. The following review will discuss several of these topics, including: fiber characterization, impact of dietary fiber on gastrointestinal physiology, energy, and nutrient digestibility, mechanical processing of feed on fiber and energy digestibility, and the use of exogenous enzymes in diets fed to growing pigs. Taken together, the diversity and concentration of chemical characteristics that exists among plant-based feed ingredients, as well as interactions among constituents within feed ingredients and diets, suggests that improvements in nutrient digestibility and pig performance from mechanical processing or adding exogenous enzymes to diets fed to swine depends on a better understanding of these characteristics, but also relating enzyme activity to targeted substrates. It may be that an enzyme must not only match a target substrate(s), but there may also need to be a 'cocktail' of enzymes to effectively breakdown the complex matrixes of fibrous carbohydrates, such that the negative impact of these compounds on nutrient digestibility or voluntary feed intake are alleviated. With the inverse relationship between fiber content and energy digestibility being well described for several feed ingredients, it is only logical that development of processing techniques or enzymes that degrade fiber, and thereby improve energy digestibility or voluntary feed intake, will be both metabolically and economically beneficial to pork production.

Effects of increasing co-product inclusion and reducing dietary protein on growth performance, carcass characteristics, and jowl fatty acid profile of growing-finishing pigs

Dietary inclusion of co-products (Co-P) provides opportunities for diversifying the feedstuff matrix by using local feedstuffs, reducing feed costs, and producing value-added pork. In 2 studies, we determined effects of Co-P (canola meal, distillers dried grains with solubles, and co-extruded oil seed and field pea) inclusion level and reduced dietary CP concentration on growth performance, carcass characteristics, and jowl fatty acid profiles of growing-finishing pigs. Pigs were fed isoenergetic and isolysinic diets over 4 growth phases with 8 pen observations per dietary regimen. At slaughter, carcasses were characterized for all pigs and jowl fat was collected from 2 pigs per pen. In Exp. 1, 1,056 pigs (initial BW, 35.3 ± 0.4 kg) were fed 3 levels of dietary Co-P (low, mid, and high) and 2 CP concentrations (low and normal). Overall (d 0 to 86), increasing Co-P inclusion from low to mid or high decreased (P < 0.001) ADFI and ADG of pigs. Low CP concentration increased (P < 0.05) ADFI and ADG compared with normal CP concentration. An interaction (P = 0.026) occurred between dietary Co-P inclusion and CP concentration for G:F; low CP reduced (P < 0.05) G:F compared with normal CP for pig fed low Co-P, but G:F did not differ between CP concentrations for pigs fed mid and high Co-P. Increasing dietary Co-P inclusion from low to high increased (P < 0.001) α-linolenic acid (ALA) in jowl fat but decreased (P < 0.001) carcass weight and loin depth. In Exp. 2, 1,008 pigs (initial BW, 30.3 ± 0.4 kg) were assigned to 5 dietary regimens with Co-P increasing from 2.0 to 50.0% or a sixth regimen with 10% extra supplemental AA for the 37.5% Co-P diet. Overall (d 0 to 97), increasing Co-P inclusion did not affect ADFI, ADG, and G:F. Increasing dietary Co-P inclusion linearly decreased (P < 0.01) carcass weight, dressing percentage, backfat thickness, and loin depth but linearly increased (P < 0.001) jowl ALA. Supplementing 10% extra AA to the 37.5% Co-P diet did not affect growth performance or dressing percentage but increased (P = 0.014) carcass leanness and decreased (P = 0.023) backfat thickness compared with the 37.5% Co-P diet, indicating that dietary AA supply did not limit BW gain. In conclusion, Co-P can be included by up to 50% in diets for growing-finishing pigs without affecting G:F. However, increasing dietary Co-P may reduce ADG, ADFI, and carcass weight even if diets are balanced for dietary NE and standardized ileal digestible AA content.

Effect of temperature level on thermal acclimation in Large White growing pigs

The effect of temperature level (24°C, 28°C, 32°C or 36°C) on performance and thermoregulatory response in growing pigs during acclimation to high ambient temperature was studied on a total of 96 Large White barrows. Pigs were exposed to 24°C for 10 days (days -10 to -1, P0) and thereafter to a constant temperature of 24°C, 28°C, 32°C or 36°C for 20 days. Pigs were housed in individual metal slatted pens, allowing a separate collection of faeces and urine and given ad libitum access to feed. Rectal (RT) and cutaneous (CT) temperatures and respiration rate (RR) were measured three times daily (0700, 1200 and 1800 h) every 2 to 3 days during the experiment. From day 1 to 20, the effect of temperature on average daily feed intake (ADFI) and BW gain (average daily gain, ADG) was curvilinear. The decrease of ADFI averaged 90 g/day per °C between 24°C and 32°C and 128 g/day per °C between 32°C and 36°C. The corresponding values for ADG were 50 and 72 g/day per °C, respectively. The 20 days exposure to the experimental temperature was divided in two sub-periods (P1 and P2, from day 1 to 10 and from day 11 to 20, respectively). ADFI was not affected by duration of high-temperature exposure (i.e. P2 v. P1). The ADG was not influenced by the duration of exposure at 24°C and 28°C groups. However, ADG was higher at P2 than at P1 and this effect was temperature dependent (+130 and +458 g/day at 32°C and 36°C, respectively). In P2 at 36°C, dry matter digestibility significantly increased (+2.1%, P < 0.01); however, there was no effect of either duration or temperature on the digestibility of dry matter at group 24°C and 32°C. RT, CT and RR were measured three times daily (0700, 1200 and 1800 h) every 2 to 3 days during the experiment. Between 28°C and 36°C, RT and CT were lower during P2 than during P1 (-0.20°C and -0.23°C; P < 0.05), whereas RR response was not affected by the duration of exposure whatever the temperature level. In conclusion, this study suggests that the effect of elevated temperatures on performance and thermoregulatory responses is dependent on the magnitude and the duration of heat stress.

Net energy of diets containing wheat-corn distillers dried grains with solubles as determined by indirect calorimetry, comparative slaughter, and chemical composition methods

The NE content of diets containing wheat-corn distillers dried grains with solubles (wcDDGS; 1:1 ratio) fed to growing pigs was determined using the comparative slaughter (CS), indirect calorimetry (IC), and chemical composition (CH) methods. The experimental diets were a corn-soybean meal control diet (CTRL), CTRL + 15% wcDDGS, and CTRL + 30% wcDDGS. In Exp. 1, 56 barrows (18.5 kg BW) were used to determine the NE value of diets using the CS method. Pigs were initially placed in 8 groups (7/group), based on BW and 1 pig/group was killed at the start of the experiment to obtain baseline body composition. The remaining 48 pigs were housed in pairs and allotted to the 3 diets (n = 8). Pigs had free access to feed and water for a 28-d period, after which 1 pig/pen was slaughtered to determine final body composition. Based on the CS method, NE values of 2,430, 2,427, and 2,429 kcal/kg DM were obtained for diets containing 0%, 15%, and 30% wcDDGS, respectively. In Exp. 2, 18 barrows (20.4 kg BW) were used to determine the NE value of diets using the IC and CH methods. Pigs were individually housed in metabolism crates and fed the 3 diets (n = 6) at 550 kcal ME/kg BW/d for a 16-d period. Feces and urine were collected from d 11 to 16, followed by measurement of O(2) consumption, CO(2) production, and urinary N, over a 36-h period using an IC system. For the IC method, NE values of 2,586, 2,513, and 2,520 kcal/kg DM were obtained for diets containing 0%, 15%, and 30% wcDDGS, respectively, and corresponding values for the CH method were 2,447, 2,451, and 2,368 kcal/kg DM, respectively. The NE values that were obtained with the CS, IC, and CH methods were not different.

Providing a diet deficient in valine but with excess leucine results in a rapid decrease in feed intake and modifies the postprandial plasma amino acid and α-keto acid concentrations in pigs

Indispensable AA are involved in the control of feed intake. When a diet deficient in Val is offered to pigs, feed intake is typically reduced. This effect is aggravated when dietary Leu is supplied in excess of the requirement. If an unbalanced supply of branched-chain AA (BCAA) is harmful, an anorectic response may serve as a mechanism to prevent this situation. We verified this hypothesis by measuring the voluntary feed intake of a balanced diet offered during the 30-min period 1 h after ingestion of a test meal deficient or not in Val (Val- and Val+) with an excess of Leu. Twelve and four 6-wk-old crossbred female pigs were used in Exp. 1 and 2, respectively. Prior ingestion of the Val- test meal resulted in a 14% reduction in feed intake compared with that observed after ingestion of the Val+ test meal (P = 0.06) in Exp. 1, indicating that the signal to reduce feed intake occurred within 1 h. It is possible that the plasma concentration of the limiting AA serves as a signal for the dietary AA deficiency. We therefore determined the postprandial plasma concentrations of BCAA and their α-keto acids after ingestion of Val- and Val+ in 4 pigs in Exp. 2. After ingestion of the Val- diet, plasma concentrations of Val and its keto acid were reduced compared with values observed after ingestion of the Val+ diet. The peak concentration occurred earlier after ingestion of the Val- diet compared with that of the Val+ diet. Although the plasma concentration increased after the meal, it declined rapidly in pigs offered Val-, and the Val concentration 4 h after ingestion of the meal was even less than that observed in the fasted state. In conclusion, it appears that the pig is able to detect a deficient supply of Val within 1 h after ingestion. The plasma concentration of Val or its concentration relative to the other BCAA during the postprandial period may act as a signal indicating the AA deficiency.

Dietary nutrient composition affects digestible energy utilisation for growth: a study on Nile tilapia (Oreochromis niloticus) and a literature comparison across fish species

The effect of the type of non-protein energy (NPE) on energy utilisation in Nile tilapia was studied, focusing on digestible energy utilisation for growth (k(gDE)). Furthermore, literature data on k(gDE) across fish species were analysed in order to evaluate the effect of dietary macronutrient composition. A total of twelve groups of fish were assigned in a 2 × 2 factorial design: two diets ('fat' v. 'starch') and two feeding levels ('low' v. 'high'). In the 'fat'-diet, 125 g fish oil and in the 'starch'-diet 300 g maize starch were added to 875 g of an identical basal mixture. Fish were fed restrictively one of two ration levels ('low' or 'high') for estimating k(gDE). Nutrient digestibility, N and energy balances were measured. For estimating k(gDE), data of the present study were combined with previous data of Nile tilapia fed similar diets to satiation. The type of NPE affected k(gDE) (0.561 and 0.663 with the 'starch' and 'fat'-diets, respectively; P < 0.001). Across fish species, literature values of k(gDE) range from 0.31 to 0.82. Variability in k(gDE) was related to dietary macronutrient composition, the trophic level of the fish species and the composition of growth (fat:protein gain ratio). The across-species comparison suggested that the relationships of k(gDE) with trophic level and with growth composition were predominantly induced by dietary macronutrient composition. Reported k(gDE) values increased linearly with increasing dietary fat content and decreasing dietary carbohydrate content. In contrast, k(gDE) related curvilinearly to dietary crude protein content. In conclusion, energy utilisation for growth is influenced by dietary macronutrient composition.

Maintenance energy requirements of growing pigs and calves are influenced by feeding level

The conventional regression method for partitioning heat production (HP) in growing animals between HP associated with either maintenance or growth assumes maintenance HP to be independent of feeding level (FL). However, there are indications that this assumption is not correct and an alternative method is proposed in this study from a reanalysis of 3 trials. In trial 1, 73-, 152-, and 237-kg calves received one milk replacer at 77, 84, 92, and 100% of their ad libitum metabolizable energy (ME) intake. In trial 2, 70-kg barrows received one diet at 60, 80, and 100% of their ad libitum ME intake {2600 kJ ME/[kg body weight (BW)(0.60) · d]}. In trial 3, 60-kg barrows received a basal diet [1700 kJ ME/(kg BW(0.60) · d)] or 4 diets consisting of the basal diet plus 850 kJ ME/(kg BW(0.60)·d) of starch alone or starch with corn gluten, casein, or vegetable oil. In the 3 trials (n = 48, 18, and 28, respectively), HP and activity-related HP were measured on individuals pigs and calves in respiration chambers for 6 d (fed state) and fasting HP (FHP; at zero activity) was calculated as the asymptotic value of HP kinetics on d 7 (feed-deprived state). The FHP changed by 0.22 kJ in calves and 0.14 kJ in pigs/kJ ME intake change during the previous days. The efficiency of using ME for maintenance and growth [k(mg); 1- (HP - FHP)/ME] was not affected by FL (calves: 84%, pigs in trial 2: 74%). In trial 3, k(mg) varied between diets in connection with variations in efficiencies between nutrients (from 55% for corn gluten to 85% for lipid). This new method of representing partitioning of ME intake considers FHP as variable with FL, does not require estimates of maintenance ME requirements, includes efficiencies that depend on diet characteristics, and is not biased by metabolic adaptations of the animal to FL.

Sow and litter response to supplemental dietary fat in lactation diets during high ambient temperatures

The objective of this experiment was to determine the impact of supplemental dietary fat on total lactation energy intake and sow and litter performance during high ambient temperatures (27 ± 3°C). Data were collected from 337 mixed-parity sows from July to September in a 2,600-sow commercial unit in Oklahoma. Diets were corn-soybean meal-based with 7.5% corn distillers dried grains with solubles and 6.0% wheat middlings and contained 3.24 g of standardized ileal digestible Lys/Mcal of ME. Animal-vegetable fat blend (A-V) was supplemented at 0, 2, 4, or 6%. Sows were balanced by parity, with 113, 109, and 115 sows representing parity 1, 2, and 3 to 7 (P3+), respectively. Feed disappearance (subset of 190 sows; 4.08, 4.18, 4.44, and 4.34 kg/d, for 0, 2, 4, and 6%, respectively; P < 0.05) and apparent caloric intake (12.83, 13.54, 14.78, and 14.89 Mcal of ME/d, respectively; P < 0.001) increased linearly with increasing dietary fat. Gain:feed (sow and litter BW gain relative to feed intake) was not affected (P = 0.56), but gain:Mcal ME declined linearly with the addition of A-V (0.16, 0.15, 0.15, and 0.14 for 0, 2, 4, and 6%, respectively; P < 0.01). Parity 1 sows (3.95 kg/d) had less (P < 0.05) feed disappearance than P2 (4.48 kg/d) and P3+ (4.34 kg/d) sows. Body weight change in P1 sows was greater (P < 0.01) than either P2 or P3+ sows (-0.32 vs. -0.07 and 0.12 kg/d), whereas backfat loss was less (P < 0.05) and loin depth gain was greater (P < 0.05) in P3+ sows compared with P1 and P2 sows. Dietary A-V improved litter ADG (P < 0.05; 1.95, 2.13, 2.07, and 2.31 kg/d for 0, 2, 4, and 6% fat, respectively) only in P3+ sows. Sows bred within 8 d after weaning (58.3, 72.0, 70.2, and 74.7% for 0, 2, 4, and 6%, respectively); conception rate (78.5, 89.5, 89.2, and 85.7%) and farrowing rate (71.4, 81.4, 85.5, and 78.6%) were improved (P < 0.01) by additional A-V, but weaning-to-breeding interval was not affected. Rectal and skin temperature and respiration rate of sows were greater (P < 0.002) when measured at wk 3 compared with wk 1 of lactation, but were not affected by A-V addition. Parity 3+ sows had lower (P < 0.05) rectal temperature than P1 and P2 sows, and respiration rate was reduced (P < 0.001) in P1 sows compared with P2 and P3+ sows. In conclusion, A-V improved feed disappearance and caloric intake, resulting in improved litter weight gain and subsequent reproductive performance of sows; however, feed and caloric efficiency were negatively affected.

Oxidation of dietary stearic, oleic, and linoleic acids in growing pigs follows a biphasic pattern

We used the pig as a model to assess the effects of dietary fat content and composition on nutrient oxidation and energy partitioning in positive energy balance. Pigs weighing 25 kg were assigned to either: 1) a low fat-high starch diet, or 2) a high saturated-fat diet, or 3) a high unsaturated-fat diet. In the high-fat treatments, 20% starch was iso-energetically replaced by 10.8% lard or 10.2% soybean oil, respectively. For 7 d, pigs were fed twice daily at a rate of 1200 kJ digestible energy · kg(-0.75) · d(-1). Oral bolus doses of [U-(13)C] glucose, [U-(13)C] α-linoleate, [U-(13)C] stearate, and [U-(13)C] oleate were administered on d 1, 2, 4, and 6, respectively, and (13)CO(2) production was measured. Protein and fat deposition were measured for 7 d. Fractional oxidation of fatty acids from the low-fat diet was lower than from the high-fat diets. Within diets, the saturated [U-(13)C] stearate was oxidized less than the unsaturated [U-(13)C] oleate and [U-(13)C] linoleate. For the high unsaturated-fat diet, oxidation of [U-(13)C] oleate was higher than that of [U-(13)C] linoleate. In general, recovery of (13)CO(2) from labeled fatty acids rose within 2 h after ingestion but peaked around the next meal. This peak was induced by an increased energy expenditure that was likely related to increased eating activity. In conclusion, oxidation of dietary fatty acids in growing pigs depends on the inclusion level and composition of dietary fat. Moreover, our data suggest that the most recently ingested fatty acids are preferred substrates for oxidation when the direct supply of dietary nutrients has decreased and ATP requirements increase.

Effects of short-term feeding of Bt MON810 maize on growth performance, organ morphology and function in pigs

Male weanling pigs (n 32) with a mean initial body weight of 7·5 kg and a mean weaning age of 28 d were used in a 31 d study to investigate the effects of feeding GM (Bt MON810) maize on growth performance, intestinal histology and organ weight and function. At weaning, the pigs were fed a non-GM starter diet during a 6 d acclimatisation period. The pigs were then blocked by weight and litter ancestry and assigned to diets containing 38·9 % GM (Bt MON810) or non-GM isogenic parent line maize for 31 d. Body weight and feed disappearance were recorded on a weekly basis (n 16/treatment), and the pigs (n 10/treatment) were killed on day 31 for the collection of organ, tissue and blood samples. GM maize-fed pigs consumed more feed than the control pigs during the 31 d study (P < 0·05) and were less efficient at converting feed to gain during days 14-30 (P < 0·01). The kidneys of the pigs fed GM maize tended to be heavier than those of control pigs (P = 0·06); however, no histopathological changes or alterations in blood biochemistry were evident. Small intestinal morphology was not different between treatments. However, duodenal villi of GM maize-fed pigs tended to have fewer goblet cells/μm of villus compared with control pigs (P = 0·10). In conclusion, short-term feeding of Bt MON810 maize to weaned pigs resulted in increased feed consumption, less efficient conversion of feed to gain and a decrease in goblet cells/μm of duodenal villus. There was also a tendency for an increase in kidney weight, but this was not associated with changes in histopathology or blood biochemistry. The biological significance of these findings is currently being clarified in long-term exposure studies in pigs.

Effect of amino acid level in the pig diet during growing and early finishing on growth response during the late finishing phase of lean meat type gilts

BACKGROUND

This experiment examined the influence of different amino acid levels during the growing and early finishing diet and the late finishing diet on growth performance and carcass quality of a lean meat type gilt. In a two by two factorial trial, 96 gilts were divided over four treatments. The two factors were (1) amino acid level in growing and early finishing and (2) amino acid level in late finishing. For the low amino acid diets we lowered the lysine, methionine, threonine and tryptophan levels by 20% and 30% in the growing and two finishing phases, respectively.

RESULTS

Restricting amino acid levels in growing and early finishing led to a decreased growth rate but improved efficiency of amino acid use, which lasted into the subsequent phase. Pigs on a high amino acid diet in late finishing pigs were able to compensate to a large extent for amino acid restriction in growing and early finishing. Amino acid content in late finishing determined carcass quality.

CONCLUSION

In the lean meat type gilts used in this experiment, restricting amino acid concentrations by 20% in the growing and 30% in the early finishing phase increased the growth rate and efficiency of growth in the subsequent late finishing phase. In order to obtain good carcass quality, it is crucial to provide the animals with a balanced diet during the late finishing phase.

Net energy of soybean oil and choice white grease in diets fed to growing and finishing pigs

The objectives of this experiment were 1) to determine the NE of soybean oil (SBO) and choice white grease (CWG) fed to growing and finishing pigs, 2) to evaluate the effects of inclusion rate of SBO on the NE by growing and finishing pigs, and 3) to determine if there is a difference in the NE of SBO and CWG between growing and finishing pigs. Forty-eight growing (initial BW: 22.13 ± 1.78 kg) and 48 finishing (initial BW: 84.17 ± 5.80 kg) barrows were used, and they were housed and fed individually. Within each stage of growth, pigs were allotted to 8 outcome groups of 6 barrows based on BW. Within each outcome group, pigs were randomly allotted to 1 of 6 groups. Two groups at each stage of growth served as an initial slaughter group. Pigs in the remaining groups were assigned to 4 dietary treatments and slaughtered at the conclusion of the experiment. The basal diet contained corn, soybean meal, and no supplemental lipids. Three additional diets were formulated by mixing 95% of the basal diet and 5% SBO, 90% of the basal diet and 10% SBO, or 90% of the basal diet and 10% CWG. Average daily gain and G:F for finishing pigs and apparent total tract digestibility of energy for growing and finishing pigs increased (linear, P < 0.05) with lipid content, but was not affected by lipid source. The lipid gain:protein gain ratio and the energy retention also increased (linear, P ≤ 0.05) with lipid content in growing and finishing pigs. There were no interactive effects between lipid content and stage of growth or between lipid source and stage of growth on the NE of diets and the NE of dietary lipids. The NE of diets increased (linear, P < 0.01) with increasing SBO (2,056, 2,206, and 2,318 kcal/kg for diets containing 0, 5, or 10% SBO). The NE of the diet containing 10% CWG (2,440 kcal/kg) was greater (P < 0.05) than the NE of the diet containing 10% SBO. The NE of diets was greater (P < 0.05) for finishing pigs than for growing pigs regardless of lipid content or source. The NE of SBO included at 5% (5,073 kcal/kg) was not different from the NE of SBO included at 10% (4,679 kcal/kg), but the NE of CWG (5,900 kcal/kg) was greater (P < 0.05) than the NE of SBO. The stage of growth had no impact on the NE of SBO or CWG. In conclusion, the NE of lipids is not affected by the content of dietary lipids, but the NE of CWG is greater than the NE of SBO.

Influence of incrementally substituting dietary soya bean meal for rapeseed meal on nutrient digestibility, nitrogen excretion, growth performance and ammonia emissions from growing-finishing pigs

A completely randomised design experiment was performed to examine the effects of replacing different levels of soya bean meal (SBM) with rapeseed meal (RSM) on the growth performance, carcass characteristics, apparent nutrient digestibility, nitrogen (N) balance and manure ammonia emissions of growing-finishing pigs. Pigs (n = 336; mean live weight 42.1 kg) were assigned to one of four dietary treatments containing per kg diet: 210 g SBM; 140 g SBM and 70 g RSM; 70 g SBM and 140 g RSM; and 210 g RSM. All diets were formulated on an ileal digestible amino acid, net energy and available phosphorus basis. There was no significant treatment effect on average daily gain, feed intake, feed conversion ratio and carcass characteristics. There was a linear decrease in gross energy digestibility (p < 0.01) as RSM increased at the expense of SBM in the diet. There was a linear decrease in urinary N excretion (p < 0.01), N digestibility (p < 0.05), total N excretion (p < 0.05) and N retention (p < 0.05) with increasing levels of RSM. There was no effect of dietary treatment on manure ammonia emissions. The results of this study indicate that RSM can be used as a direct replacement for SBM with no associated depression in performance, when formulated on an ileal digestible amino acid and net energy basis. Consumption of diets containing incremental levels of RSM linearly decreased urinary N and total N excretion, reflecting the associated decrease in crude protein concentrations.

Efeito da redução da proteína bruta e da suplementação de aminoácidos para suínos machos castrados, dos 70 aos 100kg

Estudou-se o efeito da redução da proteína bruta (PB) e da suplementação de aminoácidos em dietas para suínos, dos 70 aos 100kg. Foram utilizados 48 suínos machos, castrados, híbridos comerciais, com o peso inicial de 70,12±1,56kg, distribuídos em delineamento experimental de blocos ao acaso, com quatro níveis de proteína bruta na dieta, 17,95; 16,45; 14,95; 13,45, seis repetições e dois animais por unidade experimental. Não foi observado efeito dos tratamentos sobre o ganho de peso diário e sobre o consumo de dieta diário. Houve efeito quadrático dos níveis de PB sobre a conversão alimentar, que melhorou até o nível estimado de 15,7% de proteína bruta. Não houve influência dos níveis de PB sobre a espessura de toucinho e sobre o rendimento de carne magra. Conclui-se que a redução da proteína bruta na dieta de até 4,5 pontos percentuais, com suplementação de aminoácidos, para suínos na fase de terminação, não influi no consumo de dieta diário, no ganho de peso diário e nas características de carcaça. Melhor conversão alimentar foi estimada para suínos alimentados com dietas contendo 15,7% de proteína bruta.

Energy utilization in pigs selected for high and low residual feed intake

Genetic selection on residual feed intake (RFI) can be used as an alternative method to G:F to improve feed efficiency in pigs. The objective of this study was to determine the effects of selection for RFI on digestive and metabolic utilization of energy in 2 lines of purebred French Large White castrated male pigs obtained from a divergent selection experiment over 6 generations. The RFI(+) (high RFI) line consumed more feed than predicted from performance compared with the RFI(-) (low RFI) line. Digestibility of energy and nutrients, total heat production (HP), HP related to physical activity, and energy and N balance were measured in respiration chambers for a 6-d period in pigs offered feed ad libitum. Pigs remained in the chamber for an additional day and did not receive any feed to estimate the fasting HP and calculate the thermic effect of feeding. Five pairs of 2 littermates from the same farrowing batch were used in each line. Because 2 respiration chambers were available for the trial, pigs were measured regularly during the 25- to 95-kg growing period. Two pigs per chamber were used until pigs reached 45 kg of BW, and 1 pig per chamber was used thereafter. Individual feed intake and BW gain were measured continuously from weaning to the end of the trial. Pigs were fed 3 diets with decreasing CP contents during the 25 to 45 (period 1), 45 to 65 (period 2), and 65 to 95 (period 3) kg of BW periods. Average daily feed intake was greater in RFI(+) pigs than in RFI(-) pigs between 25 and 65 kg of BW (2,128 vs. 1,891 g/d; P < 0.01) and G:F was 8% greater in RFI(-) pigs compared with RFI(+) pigs (P < 0.01). There was no line effect on digestibility coefficients or N retention, irrespective of the experimental period studied. Nitrogen retention was 31.2, 28.7, and 20.8 g/d at periods 1, 2, and 3, respectively (P < 0.001). The HP was greater in RFI(+) pigs than in RFI(-) pigs (1,497 vs. 1,383 kJ.kg of BW(-0.60).d(-1); P < 0.01), with no subsequent line effect on energy retention. The activity-related HP tended to be greater in RFI(+) pigs than in RFI(-) pigs (250 vs. 218 kJ.kg of BW(-0.60).d(-1); P = 0.09), and the fasting HP was 10% greater (P = 0.04) in RFI(+) pigs than in RFI(-) pigs (846 vs. 771 kJ.kg of BW(-0.60).d(-1)). The thermic effect of feeding, expressed as a percentage of ME intake, was the same for both lines of pigs (average, 14.7%). In conclusion, the RFI(+) pigs are energetically less efficient because of their greater HP related to physical activity and basal metabolic rate.

The nutritional value of expeller-pressed canola meal for grower-finisher pigs

Expeller-pressed (EP) canola meal contains more residual oil than solvent-extracted canola meal and might be an attractive feedstuff for swine, but it has been poorly characterized. In Exp. 1, six ileal-cannulated barrows (36 kg of BW) were fed at 3x maintenance either a 44% EP canola meal diet or a N-free diet in a crossover design to measure energy and AA digestibility and calculate standardized ileal digestible (SID) AA and NE content, with 6 observations per diet. Each period consisted of a 5-d diet adaptation and a 2-d feces and 3-d digesta collection. The EP canola meal contained (% of DM) 38.5% CP, 13.3% ether extract, 2.42% Lys, 1.54% Thr, 0.62% Met, and 23.2 micromol/g of glucosinolates. Apparent total tract energy digestibility was 75.0% and the DE and predicted NE content were 3.77 and 2.55 Mcal/kg (in DM), respectively. The SID AA content (% of DM) was 1.77% Lys, 1.04% Thr, and 0.52% Met. In Exp. 2, a total of 1,100 pigs (25 kg of BW) housed in 50 pens were fed 5 dietary regimens with 0, 7.5, 15, and 22.5% or decreasing amounts (22.5, 15, 7.5, and 0%, respectively) of EP canola meal over 4 phases to validate performance and carcass characteristics. Diets were formulated to contain equal NE:SID Lys for each growth phase (g/Mcal; 4.04, d 0 to 25; 3.63, d 26 to 50; 3.23, d 51 to 77; 2.83, d 78 to 90). At slaughter, carcass characteristics were measured for all pigs, and jowl fat was sampled for 2 pigs per pen. For d 51 to 90, the 22.5% EP canola meal regimen was reduced to 18% (22.5/18%) because of decreased ADFI in phases 1 and 2. Overall (d 0 to 90), increasing dietary EP canola meal linearly decreased (P < 0.001) ADG and ADFI and linearly increased (P < 0.01) G:F. For 0 and 22.5/18% EP canola meal, respectively, ADG was 978 and 931 g/d, ADFI was 2.77 and 2.58 kg/d, and G:F was 0.366 and 0.378. Increasing dietary EP canola meal did not alter the carcass backfat thickness, loin depth, or jowl fat fatty acid profile. Pigs fed 22.5/18% EP canola meal reached slaughter weight 3 d after (P < 0.05) pigs fed 0% EP canola meal. In summary, EP canola meal provided adequate energy and AA; however, ADG was reduced by 3 g/d per 1% of EP canola meal inclusion, likely because of increased dietary glucosinolates. Thus, the amount of EP canola meal included in swine diets should be targeted to an expected growth performance and carcass quality. Finally, diets formulated to contain an equal NE and SID AA content did not entirely eliminate the risks for reduced growth performance associated with inclusion of an alternative feedstuff.

Digestibilidade da silagem de grãos úmidos de milho com diferentes granulometrias para suínos

Avaliou-se a composição química e determinaram-se os valores de energia digestível (ED) e metabolizável (EM), os coeficientes de digestibilidade da matéria seca (CDMS), da proteína bruta (CDPB), da matéria mineral (CDMM); do extrato etéreo (CDEE); da fibra bruta (CDFB), da energia bruta (CDEB) e do extrativo não nitrogenado (CDENN) e os coeficientes de digestibilidade (CDEB) e metabolizabilidade da energia bruta (CMEB) da silagem de grãos úmidos de milho (SGUM). Foram utilizados 20 suínos, com peso vivo inicial de 28,89±4,9kg, distribuídos em gaiolas de metabolismo. Foi utilizada uma única SGUM, com quatro diferentes granulometrias 513, 587, 717 e 1363µm, que substituiu em 30% a dieta-referência. Os CDMS, CDPB, CDEE, CDMM e CDENN diminuíram com o aumento da granulometria da SGUM. Os CDEB e CMEB também diminuíram de 89,0 para 94,3%, e de 82,9 para 88,5%, respectivamente. Os valores energéticos variaram de 4439 a 4493kcal EB/kg, de 3999 a 4194kcal ED/kg e de 3729 a 3939kcal EM/kg, na matéria seca. Os CDEB e CMEB se reduziram até os diâmetros geométricos médios de 754 e 831µm, respectivamente. A digestibilidade dos nutrientes da SGUM foi influenciada negativamente ao se aumentar o diâmetro geométrico médio das partículas.

Characterization of the nutritional value of air-classified protein and starch fractions of field pea and zero-tannin faba bean in grower pigs

Most pulse (nonoilseed legume) seed flours can be fractionated rapidly and economically by air classification into protein and starch concentrates. The nutritional value of air-classified field pea and faba bean concentrates requires characterization to assess the feeding opportunity for pigs. Thus, the objectives were to characterize the apparent total tract digestibility (ATTD) of DM, OM, energy, starch, CP, fat, and ash; apparent ileal digestibility of CP and starch; standardized ileal digestibility (SID) of AA; and the SID AA, DE, and NE content of air-classified zero-tannin faba bean and field pea protein and starch concentrates in grower pigs. Pulse protein and starch concentrates were compared with soy protein concentrate and corn starch, respectively, as corresponding standards. The corn starch diet served as an N-free diet to correct for basal endogenous AA losses. In a Youden square design, 8 ileal-cannulated barrows (24.9 +/- 2.3 kg of BW) were fed 6 diets over 7 periods at 3 times the maintenance DE requirement. Periods encompassed a 5-d diet acclimation, 3-d feces collection, and 3-d ileal digesta collection. The ATTD of GE was 2% greater (P < 0.05) for faba bean than soy and was intermediate for field pea protein (95.6, 93.7, and 94.9%, respectively). The ATTD of GE was 3.6% greater (P < 0.05) for corn and field pea than faba bean starch (96.2, 95.1, and 92.3%, respectively). The DE content of faba bean was 5.0% greater (P < 0.05) than for field pea or soy protein (4.47, 4.23, and 4.26 Mcal/kg, respectively). The DE content of faba bean and field pea was 1.7% greater (P < 0.05) than for corn starch (3.72, 3.77, and 3.68 Mcal/kg, respectively). The NE content was 5% greater (P < 0.05) for faba bean than field pea and soy protein (3.08, 2.94, and 2.92 Mcal/kg, respectively). The NE content for field pea starch was 2.0% greater (P < 0.05) than for corn starch and faba bean starch (2.68, 2.63, and 2.61 Mcal/kg, respectively). Protein concentrates had a 14 and 11% greater (P < 0.05) DE and NE content, respectively, than starch concentrates. The SID of Lys was 6.0% greater (P < 0.05) for faba bean and field pea protein than soy protein (95.5, 92.6, and 88.7%, respectively). The SID of Lys was 6.0% greater (P < 0.05) for faba bean than field pea starch. Nutrient digestibility and digestible nutrient profiles indicated that air-classified fractions of zero-tannin faba bean and field pea constitute concentrated sources of AA and energy for pigs with high nutritional demands.