Methane emission by growing pigs and adult sows as influenced by fermentation

The fermentation of carbohydrates in pigs' digestive system, especially in the lower gut results predominantly in short chain fatty acids, gasses as CO₂, H₂ and CH₄. Methane (CH₄) is especially interesting as it contributes to the greenhouse gas emission and thus also to the global warming. CH₄ production and its relation to fermentation in growing pigs (74 diets) as well as adult sows (36 diets), were investigated in diets varying greatly in chemical composition. All diets were assayed in digestibility and energy balance experiments in respiration chambers. Growing pigs fed diets varying in total fibre content (2.8–40%) had a CH₄ production equivalent to 0.1 to 1.3% of digested energy (DE). Non-lactating sows fed at maintenance had a CH₄ production equivalent to 0.4 to 3.3 % of DE. Intensively fed lactating sows had the lowest CH₄ production (about 0.6% of DE). In general, the production of methane depended on fibre origin, however high variation was found between animals.     

Feeding high fibre diets changes luminal environment and morphology in the intestine of sows

Sows were fed three diets varying in type and level of dietary fibre (DF). The low fibre diet (LF; 17% DF) was based on wheat and barley. In the two high DF diets (HF1, high in soluble DF and HF2, high in insoluble DF;  44% DF), the cereal part of the diet was substituted with different co-products (sugar beet pulp, potato pulp, pectin residue, pea hull, brewer's spent grain, and seed residue). The diets were fed for a four-week period to 12 sows (4 for each diet). Sows were stunned 4 h post-feeding, and digesta and tissue samples were collected from various parts of the small and large intestines. The carbohydrate load to the large intestine was 538–539 g/d when feeding the high DF diets and 190 g/d when feeding diet LF. Feeding sows the high DF diet containing large proportion of soluble DF resulted in a lower dry matter content of digesta (23 contra 28%), a higher tissue weight (2.9 contra 2.0 kg), and a higher crypt depth (492 contra 330 μm) and area (23,201 contra 15,751 μm²) in the colon compared with the low DF diet. In conclusion, increasing the amount of DF in the diet for sows resulted in an increased amount of digesta entering the large intestine which influences the functional properties of digesta. Furthermore, a high DF diet with a high proportion of soluble DF increases tissue weight, crypt depth and crypt area in the midcolon compared to a low fibre diet.     

Digestion of carbohydrates and utilization of energy in sows fed diets with contrasting levels and physicochemical properties of dietary fiber

Three experimental diets were used to investigate the digestion of carbohydrates and utilization of energy in sows fed diets with different levels and physicochemical properties of dietary fiber (DF). The low-fiber diet (LF; DF, 16%; soluble DF, 4.8%) was based on wheat and barley. The high-fiber 1 diet (HF1; DF, 41%; soluble DF, 11%) was based on wheat and barley supplemented with the coproducts: sugar beet pulp, potato pulp, and pectin residue, and the high-fiber 2 diet (HF2; DF, 44%; soluble DF, 7.3%) was based on wheat and barley supplemented with approximately 1/3 of the coproducts used in diet HF1 and 2/3 of brewers spent grain, seed residue, and pea hull (1:1:1, respectively). The diets were studied in 2 series of experiments. In Exp. 1, the digestibility and ileal and fecal flow of nutrients were studied in 6 ileal-cannulated sows placed in metabolic cages designed as a repeated 3 x 3 Latin square design. In Exp. 2, energy metabolism was measured in respiration chambers using 6 sows in a repeated 3 x 3 Latin square design. The DF level influenced the ileal flow of most nutrients, in particular carbohydrates, which increased from 190 g/d when feeding the LF diet to 538 to 539 g/d when feeding the HF diets; this was also reflected in the digestibility of OM and carbohydrates (P < 0.05). The ranking of total excretion of fecal materials was HF2 > > HF1 > LF, which also was reflected in the digestibility of OM, protein, and carbohydrates. Feeding HF diets resulted in greater CH(4) production, which was related to the amount of carbohydrates (r = 0.79) and OM (r = 0.72) fermented in the large intestine, but with no difference in heat production (12.2 to 13.1 MJ/kg of DM). Retained energy (MJ/kg of DM) was decreased when feeding HF1 compared with LF and negative when feeding HF2. Feeding sows HF1 reduced the activity of animals (5.1 h/24 h) compared with LF (6.1 h/24 h; P = 0.045).     

Comparative total tract digestibility of dietary energy and nutrients in growing pigs and adult sows

Seventy-seven diets were fed to 61-kg growing pigs at a feeding level close to their ad libitum intake and to nonlactating, nonpregnant sows slightly above their maintenance energy level (2.4 kg/d). The main objectives of this study were to compare the total tract digestibility of dietary energy or nutrients of the 77 diets in growing pigs and adult sows and to analyze the effect of diet chemical composition on total tract digestibility in both groups of pigs. Diets were formulated to represent a range of chemical compositions as large as those found in most practical situations. The DE and ME values and total tract digestible nutrient contents of diets were measured for each group of animals; each diet was measured in four to five animals per group, and collection of urine and feces lasted 10 d. The results were used to establish equations for predicting DE and ME values, total tract digestible nutrient contents, and total tract digestibility coefficients of energy from chemical characteristics for each group of animals. The results show that the total tract digestibility of energy or nutrients was higher (P < 0.01) in adult sows than in growing pigs; the total tract digestibility coefficients of energy, crude protein, ether extract, and NDF averaged 85.2, 85.1, 37.1, and 64.4%, respectively, for sows and 82.1, 80.3, 31.6, and 56.3%, respectively, for growing pigs. The ME/DE ratio was lower (P < 0.01) in sows (94.8%) than in growing pigs (96.5%), as a result of higher urinary energy losses in sows. The difference in DE values (on average, 0.6 MJ/kg of DM) between adult sows and growing pigs was not constant (P < 0.01) but increased with dietary fiber content (3.3, 8.6, and 10.1 kJ for each gram of NDF, ADF, and crude fiber increase in the diet, respectively), which suggests that the origin of the difference between the two physiological stages is mainly due to a higher rate of degradation of dietary fiber in the hindgut of sows. The DE and ME values could be accurately predicted from total tract digestible nutrients or from chemical characteristics for each physiological stage. Equations for predicting urinary energy loss from urinary N are also proposed. From a practical point of view, it is suggested to use two energy values for pig feeds: one applicable to growing-finishing pigs and one to adult sows. Equations for predicting DE in adult sows from energy values obtained in growing pigs are proposed.     

Effects of a novel bacterial phytase expressed in Aspergillus Oryzae on digestibility of calcium and phosphorus in diets fed to weanling or growing pigs

In 2 experiments, 48 weanling (initial BW: 13.5 ± 2.4 kg, Exp. 1) and 24 growing pigs (initial BW: 36.2 ± 4.0 kg, Exp. 2) were used to determine effects of a novel bacterial 6-phytase expressed in Aspergillus oryzae on the apparent total tract digestibility (ATTD) of phosphorus and calcium in corn-soybean meal diets fed to weanling and growing pigs. In Exp. 1 and 2, pigs were randomly allotted to 6 dietary treatments using a randomized complete block design and a balanced 2 period changeover design, respectively. In both experiments, 6 diets were formulated. The positive control diet was a corn-soybean meal diet with added inorganic phosphorus (Exp. 1: 0.42 and 0.86% standardized total tract digestible phosphorus and total calcium, respectively; Exp. 2: 0.32 and 0.79% standardized total tract digestible phosphorus and total calcium, respectively). A negative control diet and 4 diets with the novel phytase (Ronozyme HiPhos, DSM Nutritional Products Inc., Parsippany, NJ) added to the negative control diet at levels of 500, 1,000, 2,000, and 4,000 phytase units (FYT)/kg were also formulated. In Exp. 1, the ATTD of phosphorus was greater (P < 0.01) for the positive control diet (60.5%) than for the negative control diet (40.5%), but increased (linear and quadratic, P < 0.01) as phytase was added to the negative control diet (40.5% vs. 61.6%, 65.1%, 68.7%, and 68.0%). The breakpoint for the ATTD of phosphorus (68.4%) was reached at a phytase inclusion level of 1,016 FYT/kg. In Exp. 2, the ATTD of phosphorus was greater (P < 0.01) for the positive control diet (59.4%) than for the negative control diet (39.8%) and increased (linear and quadratic, P < 0.01) as phytase was added to the negative control diet (39.8% vs. 58.1%, 65.4%, 69.1%, and 72.8%). The breakpoint for the ATTD of phosphorus (69.1%) was reached at a phytase inclusion level of 801 FYT/kg. In conclusion, the novel bacterial 6-phytase improved the ATTD of phosphorus and calcium in both weanling and growing pigs. The optimum level of inclusion for this phytase is 800 to 1,000 FYT/kg of complete feed to maximize ATTD of phosphorus and calcium in weanling and growing pigs.     

Evaluation of diets contaminated with aflatoxin and ochratoxin fed to growing pigs

The effects of dietary aflatoxin and ochratoxin, fed singly and in combination, were evaluated in growing crossbred pigs. Five barrows (7 weeks old at beginning of study) per group were fed either control feed, 2.0 mg of aflatoxin (AF)/kg of feed, 2.0 mg of ochratoxin (OA/kg of feed, or 2.0 mg of AF and 2.0 mg of OA/kg of feed for 28 days. Production performance, serum biochemical, hematologic, and pathologic evaluations were made. Body weights were reduced by the combination treatment, whereas body weight gain was decreased by all toxin treatments. The effect of AF and OA in combination on body weight gain was additive. Liver weights were increased by the combination treatment, whereas kidney weights were increased only in the OA group. Aflatoxin caused decreases in serum calcium, sodium, phosphorus, urea nitrogen, cholesterol, and glucose concentrations, whereas OA alone caused decreases in serum phosphorus, cholesterol, and hematologic values. The AF-OA treatment induced decreases in mean corpuscular volume, packed cell volume, and in serum concentrations of phosphorus, cholesterol, and urea nitrogen. The AF-OA treatment increased serum alkaline phosphatase activities and triglycerides. It was concluded that AF and OA, singly or in combination, can affect clinical performance, serum biochemical and hematologic values, and organ weights of barrows. Although values of some measurements were affected more by the combination than by either toxin alone and suggested synergism or antagonism, the toxic interactions could best be described as additive.     

Phyzyme XP phytase improves growth performance and nutrient utilization in wheat-based diets fed to weaned pigs

The effect of phytase (Phyzyme XP) on performance and nutrient utilization in piglets fed wheat-based diets was evaluated using 24 male pigs averaging 7 kg. Four experimental diets containing either 0 (positive control, adequate nutrients), 0 (negative control (NC), reduced nutrients), 500 or 1000 U/kg of phytase were used for each of two dietary phases (day 0 to 14 and day 14 to 33). Feed and water were provided ad libitum. Animals were weighed at weekly intervals until day 28 and feed intake (DFI) recorded daily. From day 28 to 33 pigs were fed at 3 times maintenance energy intake and DFI recorded. Total amounts of faeces and urine were recorded for each individually housed pig. Digestibilities and balance of dry matter (DM), phosphorus (P), calcium (Ca), nitrogen (N) and gross energy (GE) were calculated for feed, faeces and urine. Compared to the NC, daily live weight gain was improved (P < 0.05) for pigs receiving the highest level of supplemental phytase in phase 2. Phytase addition at 1000 FTU/kg also increased faecal digestibilities of P and Ca (P < 0.05). Contrasts comparing NC and Phytase diets showed that Ca (P < 0.02) and P (P < 0.05) balance were improved.     

Effect of dietary inclusion of benzoic acid on mineral balance in growing pigs

The objective of this study was to determine the effect of dietary inclusion of benzoic acid on utilization of the macrominerals Ca, P, Mg, K, Na, and Cl in growing pigs. Eighteen barrows, initial BW of 28 ± 1.7 kg, were assigned to 3 diets: a basal diet based on barley, wheat, soybean meal, corn, and field pea and formulated to contain 9.31 MJ NE kg^− 1 and 8.84 g^− 1 kg standardized ileal digestible lysine, or the basal diet containing 10 or 20 g kg^− 1 benzoic acid by replacing tapioca starch. The pigs were fed the experimental diets a rate of 2.7 times the maintenance requirement for ME for 21 days. Faeces and urine were collected quantitatively from days 11 to 21, and blood and plasma was collected on days 1, 10, and 21. On day 21, the pigs were killed and the left femur was removed. Benzoic acid linearly decreased (P = 0.001) the urine pH from 7.32 to 5.32, and quadratically increased (P < 0.05) blood pH on day 21. Benzoic acid linearly increased (P < 0.05) the apparent total tract digestibility (ATTD) of Ca, P, and Na from 65 to 72%, 46 to 55%, and 78 to 90%, respectively, linearly decreased (P < 0.05) the ATTD of Cl from 94 to 93%, and did not affect the ATTD of Mg and K. Benzoic acid linearly increased (P < 0.05) the retention of Ca, P, and K from 58 to 67%, 46 to 54%, and 31 to 38%, respectively, linearly decreased (P < 0.05) the retention of Na and Cl from 57 to 48% and 75 to 44%, respectively, and did not affect retention of Mg. On day 21, benzoic acid linearly increased (P = 0.001) plasma P and quadratically increased (P < 0.05) plasma K or tended to increase (P = 0.05) plasma Na. Benzoic acid linearly reduced (P < 0.05) the concentration of ash in femur but not the amount of ash, reduced (P < 0.05) the concentration of Ca and Cl in femur ash, and linearly increased (P < 0.05) the concentration of P in femur ash. In summary, benzoic acid increased the utilization of dietary Ca, P, and K, did not affect the utilization of dietary Mg, and reduced the utilization of dietary Na and Cl. During swine feed formulation, effects of benzoic acid on macromineral utilization should be considered to ensure that macromineral requirements are met and not exceeded following benzoic acid supplementation.     

The energy preservation requirements of growing pigs of different sexes fed normal and high protein diets. 5. Comparison with the results obtained from castrated pigs, sows and boars

In one experiment each with castrated pigs, sows and boars (hybrid pigs of line 150), two groups of six animals received rations containing 17 and 45% crude protein resp. over the complete test period from 35 to 130 kg (castrated pigs), 150 kg (sows), 170 kg live weight (boars) and passed alternatively through a total of 60 metabolism periods on growth and 48 on maintenance level. There were significant differences between the 3 categories of animals with regard to energy maintenance requirement in the relation of 100:105:110 for castrated pigs less than sows less than boars. In contrast to the estimated values derived from previous studies for energetic maintenance requirement of 650 kJ/kg LW0.62.d the measured values for all 3 animal categories are by approximately 50% higher. The protein content did not have an influence on the maintenance requirement of metabolizable energy of the animals. The utilization of metabolizable energy of the two rations for body energy retention corresponds to the expectations with regard to its dependence on nutrients. The requirement of metabolizable energy for protein and fat retention is 1.7:1.0. The energy content of the weight gain of boars was, on average, 85% of that of castrated pigs and sows. The studies of blood parameters did not show any deviations in the parameters tested.     

Ileal amino acid digestibility and performance of growing pigs fed wheat-based diets supplemented with xylanase

Two experiments were conducted to determine the effect of supplementation of xylanase to a wheat-based diet on the apparent ileal digestibility (AID) of AA and the performance of growing pigs fed diets limiting in AA. In Exp. 1, eight pigs (average initial BW = 20.5+/-1.2 kg) fitted with a simple T-cannula at the distal ileum, were fed four diets according to a repeated 4 x 4 Latin square design. Diet 1 was a basal diet that contained 97.6% wheat. Diets 2, 3, and 4 were the basal diet supplemented with xylanase at rates of 5,500, 11,000, and 16,500 units of xylanase activity (XU), respectively (as-fed basis). There were linear and quadratic effects (0.062 < P < 0.001) of xylanase supplementation on the AID of CP and most of the AA. The largest increases in AID of CP and AA were obtained when xylanase was supplemented at a rate of 11,000 XU; no further increases were observed with xylanase supplementation at a rate of 16,500 XU. In Exp. 2, 30 pigs (average initial BW 21.4+/-1.8 kg) were randomly allotted to six dietary treatments. Diets 1 to 4 were similar to those used in Exp. 1. Diet 5 was the same as Diet 1, but supplemented with 0.53% lysine, 0.12% threonine, and 0.05% methionine. Diet 6 (positive control diet) was a wheat-soybean meal diet that contained 18.2% CP (as-fed basis). The total contents of lysine, threonine, and methionine were similar for Diets 5 and 6. There was a linear effect of xylanase supplementation on ADG (P = 0.093) and feed:gain ratio (P = 0.089), and a quadratic effect on ADG (P = 0.067) and feed:gain ratio (P = 0.074). But, the greatest response was obtained with the supplementation of 11,000 XU. The supplementation of lysine, threonine, and methionine to Diet 1 increased (P = 0.001) ADG and ADFI and improved (P = 0.01) feed:gain ratio. There was no difference (P = 0.508) in the performance of pigs fed the AA-supplemented or control diet. In conclusion, the supplementation of xylanase to a diet in which wheat provided the sole source of protein and energy improved the AID of AA, ADG, and feed:gain ratio; however, this improvement was very small compared with that obtained with the supplementation of synthetic amino acids.     

Estimation of endogenous phosphorus loss in growing and finishing pigs fed semi-purified diets

Thirty-six barrows were used in a series of 3 P-balance experiments in which growing and finishing pigs were fed highly digestible, semi-purified diets at or below the dietary available P requirement to estimate the effect of BW on endogenous P loss. Experiments 1, 2, and 3 were conducted with pigs averaging 27, 59, and 98 kg of BW, respectively. In each experiment, pigs were placed in metabolism crates and allotted by weight and litter to 3 dietary treatments. The basal diet consisted of sucrose, dextrose, cornstarch, and casein fortified with minerals (except P) and vitamins. Diets 1, 2, and 3 in Exp. 1 were the basal diet with 0, 0.078, or 0.157% added P, respectively, from monosodium phosphate. In Exp. 2 and 3, diets 1, 2, and 3 were the basal diet with 0, 0.067, and 0.134% added P, respectively, from monosodium phosphate. Within replicate, pigs were fed equal amounts of feed twice daily. Pigs were adjusted to treatments for 7 d before a 6-d, marker-to-marker collection of feces and urine. Phosphorus intakes for pigs fed the 3 diets ranged from 1.73 to 3.91 g/d in Exp. 1, from 2.18 to 5.32 g/d in Exp. 2, and from 1.96 to 6.26 g/d in Exp. 3. Fecal P excretion and P absorption increased linearly (P < 0.05) with increasing P intake. In the 3 experiments, urinary P excretion (g/d) was low for pigs fed diet 1 (0.010, 0.011, 0.019) and diet 2 (0.013, 0.058, 0.084) and was low for pigs fed diet 3 in Exp. 1 (0.037); however, urinary P was greater in pigs fed diet 3 in Exp. 2 and 3 (0.550 and 0.486, respectively). When P absorption (Y, g/d) was regressed on P intake (X, g/d) in Exp. 1, 2, and 3, the relationships were linear (P < 0.01): Y = -0.110 + 0.971X (R2 = 0.999), Y = -0.156 + 0.939X (R2 = 0.998), and Y = -0.226 + 0.8919X (R2 = 0.982), respectively. Thus, our estimates of endogenous P loss at zero P intake were 110, 156, and 226 mg/d for 27-, 59-, and 98-kg pigs, respectively. When these Y-intercepts were regressed on BW, the relationship was Y = 63.06 + 1.632X (R2 = 0.996), where Y = endogenous P loss in mg/d and X = BW in kg. Based on these data, we estimate the endogenous P loss of pigs fed highly digestible, semi-purified diets to increase by approximately 1.632 mg for each 1-kg increase in BW from 25 to 100 kg.     

The effects of dietary fiber level on nutrient digestibility in growing pigs

The objective of this study was to investigate the effects of total dietary fiber level on nutrient digestibility and the relationship between apparent total tract digestibility of total dietary fiber, and soluble dietary fiber, insoluble dietary fiber and available energy. Sugar beet pulp was as the only fiber source. The experiment was designed as a 6 × 6 Latin square with an adaptation period of 7 d followed by a 5-d total collection of feces and urine. Feed intake tended to decrease (P =0.10) as total dietary fiber level increased. The apparent total tract digestibility of dry matter, crude protein and gross energy decreased (P <0.01) when total dietary fiber increased but the digestibility of soluble dietary fiber and insoluble dietary fiber increased (P <0.01). The digestible energy and metabolizable energy content of diets decreased (P <0.01) as the total dietary fiber increased.     

The effects of dietary fiber level on nutrient digestibility in growing pigs

The objective of this study was to investigate the effects of total dietary fiber level on nutrient digestibility and the relationship between apparent total tract digestibility of total dietary fiber, and soluble dietary fiber, insoluble dietary fiber and available energy. Sugar beet pulp was as the only fiber source. The experiment was designed as a 6 x 6 Latin square with an adaptation period of 7 d followed by a 5-d total collection of feces and urine. Feed intake tended to decrease （P =0.] O） as total dietary fiber level increased. The apparent total tract digestibility of dry matter, crude protein and gross energy decreased （P 〈0.0]） when total dietary fiber increased but the digestibility of soluble dietary fiber and insoluble dietary fiber increased （P 〈0.01）. The digestible energy and metabolizable energy content of diets decreased （P 〈0.01） as the total dietary fiber increased.     

Nutrient digestibility and performance responses of growing pigs fed phytase- and xylanase-supplemented wheat-based diets

Three experiments were conducted to evaluate the effect of supplementing phytase and xylanase on nutrient digestibility and performance of growing pigs fed wheat-based diets. In Exp. 1, 10 diets were fed to 60 pigs from 20 to 60 kg of BW to determine the effect of combining phytase and xylanase on apparent total tract digestibility (ATTD) of nutrients and growth performance. The 10 diets included a positive control diet (PC; 0.23% available P; 0.60% Ca) and a negative control diet (NC; 0.16% available P; 0.50% Ca) supplemented with phytase at 0, 250, and 500 fytase units (FTU)/kg and xylanase at 0, 2,000, and 4,000 xylanase units (XU)/kg in a 3 x 3 factorial arrangement. In Exp. 2, 6 ileally cannulated barrows (initial BW = 35.1 kg) were fed 4 wheat-based diets in a 4 x 4 Latin square design, with 2 added columns to determine the effect of combining phytase and xylanase on apparent ileal digestibility (AID) of nutrients. The 4 diets were NC (same as that used in Exp. 1) or NC supplemented with phytase at 500 FTU/kg, xylanase at 4,000 XU/kg, or phytase at 500 FTU/kg plus xylanase at 4,000 XU/kg. In Exp. 3, 36 barrows (initial BW = 55.5 kg) were fed 4 diets based on prepelleted (at 80 degrees C) and crumpled wheat for 2 wk to determine the effect of phytase supplementation on ATTD of nutrients. The 4 diets fed were a PC (0.22% available P; 0.54% Ca) and a NC (0.13% available P; 0.43% Ca) alone or with phytase at 500 or 1,000 FTU/kg. All diets in the 3 experiments contained Cr(2)O(3) as an indigestible marker. No synergistic interactions were detected between phytase and xylanase on any of the response criteria measured in Exp. 1 or 2. There were no dietary effects on growth performance in Exp. 1. In Exp. 1, phytase at 250 FTU/kg increased the ATTD of P and Ca by 51 and 11% at 20 kg of BW or by 54 and 10% at 60 kg of BW, respectively, but increasing the level of phytase to 500 FTU/kg only increased (P < 0.05) ATTD of P at 20 kg of BW. In Exp. 2, phytase at 500 FTU/kg increased (P < 0.05) the AID of P and Ca by 21 and 12%, respectively. In Exp. 3, phytase at 500 FTU/kg improved (P < 0.05) ATTD of P by 36%, but had no further effect at 1,000 FTU/kg. Xylanase at 4,000 XU/kg improved (P < 0.05) AID of Lys, Leu, Phe, Thr, Gly, and Ser in Exp. 2. In conclusion, phytase and xylanase improved P and AA digestibilities, respectively, but no interaction between the 2 enzymes was noted.     

Performance of growing pigs fed diets based on by-products of maize and wheat processing

Forty-eight crossbred Landrace?×?Large white pigs with an average body weight of 8.5?±?0.4 kg and aged 2 months were used to evaluate performance and carcass characteristics of pigs fed two diets in which bran from maize or wheat was used as the energy source. A third diet based on whole maize grain was used as a control. Animals in groups of four, balanced for litter, sex and weight were allotted to dietary treatments in a completely randomised design with four replications. Data were collected on feed intake and weight gain for a period of 4 months. A digestibility trial was carried at the end of the feeding trial using two male pigs per treatment while six pigs per treatment were randomly selected for slaughter to determine carcass characteristics. Daily gain averaged 0.23, 0.31 and 0.13 kg/day, for pigs fed maize bran, wheat bran and whole maize diets, respectively. Average feed intake and final body weight were significantly (P?<?0.05) affected by diets. Digestibility of dry matter, crude fibre and calcium were higher (P?<?0.05) for pigs fed maize bran while crude protein digestibility was highest (P?<?0.05) for the pigs fed wheat bran. There were significant differences (P?<?0.05) between the diets in carcass yield, ham, head, trotters and heart weights and also for rib weight, rib eye muscle and other tissues. This study indicates that comparable performance of growing pigs fed cereal bran and full-grain diets are real.     

Growth performance and puberty attainment in growing pigs fed dietary fumonisin B1

Twenty‐four male weaned piglets assigned to four diets containing 5.0, 10.0, 15.0 and 0.2 mg fumonisin B₁ (FB₁) /kg as diets 1, 2, 3 and control diet, respectively, were used to study the effect of dietary FB₁ on growth and puberty attainment in pigs in a 6‐month feeding trial. Lower feed intake during 0–4 months and a non‐significant (p > 0.05) but FB₁ concentration‐dependent decrease in live and DWGs in animals fed FB₁‐contaminated diets was observed at the end of the pubertal phase. The daily and the final live weight gains of animals fed diet 3 were 75.8% and 90.6%, respectively, of the control values. The mean ages at puberty by boars on diets 2 and 3 were significantly (p < 0.05) higher than those for animals on the control and diet 1. The animals on diet 3 attained puberty when mean live weight was 60.1 kg, some 30.3 days after the controls attained puberty, at 156.3 days, when the mean live weight was 46.9 kg. This study revealed that dietary FB₁ delays sexual maturity in growing pigs. Male weanling pigs for breeding should not be exposed to dietary FB₁ higher than 5 mg/kg for optimum growth and reproductive performance.     

Nutrient utilization and manure P excretion in growing pigs fed corn-barley-soybean based diets supplemented with microbial phytase

The effect of high levels of microbial phytase supplementation in diets for growing pigs was studied in a 2‐week performance and nutrient digestibility trial involving 28 growing pigs weighing 16.4 ± 1.06 (mean ± SD) kg. Seven corn‐barley‐soybean meal‐based diets consisting of a positive control (PC) formulated to meet or exceed NRC nutrient requirements; a negative control (NC) with non‐phytate P reduced by 0.1% unit from NRC requirement and fed without or with 500 or 1000 U/kg; a doubled negative control (DNC) with no added inorganic P and fed without or with 2000 or 4000 U/kg. Chromic oxide was added as an indigestible marker and all diets were fed as mash. Pigs fed the PC diet had a higher P digestibility compared with those fed the NC (P < 0.02) and the DNC (P < 0.001) diets. Supplementing the NC diet with pyhtase tended to improve P digestibility (P < 0.10). However, addition of phytase to the DNC diet resulted in linear (P < 0.001) and quadratic (P < 0.03) increases in P digestibility with an overall improvement of 8% and 121% at 4000 phytase U/kg of diet, respectively, compared with the PC and DNC diets. Apparent total tract digestibility of N, OM and DM were higher (P < 0.05) in the PC diet compared with the DNC diet, but not the NC diet (P < 0.10). No effect of phytase addition to NC was observed on Ca, N, DM and OM digestibility. Phytase addition to the DNC diet resulted in a linear increase (P < 0.05) in N, DM and OM digestibility but not Ca. Increasing the levels of phytase supplementation in the NC and the DNC diets linearly decreased fecal P (P < 0.05) content by 45 and 42%, respectively. Adding phytase at 1000 or 4000 U/kg increased P retention (P < 0.05) by 14.3 or 15.6% units, respectively, compared with the PC diet. Urinary P excretion was higher in the group fed the PC diet compared with those fed the NC and DNC diets (P < 0.05). The results of this study show that complete removal of inorganic P from growing pig diets coupled with phytase supplementation improves digestibility and retention of P and N, thus reducing manure P excretion without any negative effect on pig performance.     

Influence of guanidination on apparent ileal digestibility of amino acids in pigs fed diets with soybean meal, rapeseed meal or peas as a protein source

The objective of this study was to determine the effect of guanidination, the conversion of dietary lysine to homoarginine, on the apparent ileal digestibilities (AID) of amino acids (AA) from 3 protein sources in diets for pigs. Six barrows, initial body weight of 18 ± 1.5 kg, fitted with a simple T-cannula at the distal ileum, were fed one of three corn starch-based diets that contained 18% crude protein (CP) from soybean meal, rapeseed meal or peas for an experimental period of 10 d according to a repeated 3 × 3 Latin square design. On d 9 of each experimental period, the pigs were fed one meal of the guanidinated test meals, which corresponded to their respective diets. In the test meals, 50% of the protein source in each diet was replaced, on an equal weight basis, with a guanidinated source. Guanidination increased the content of CP by 190, 116 and 28 g kg^− 1 for soybean meal, rapeseed meal and peas, respectively. With the exception of lysine, the AID of CP and AA were 2.2 to 8.2 percentage units (pu) higher in the test meal than in the soybean meal diet. Other than arginine and isoleucine, the differences were significant (P < 0.05) for all indispensable AA. With the exception of lysine, the AID of CP and AA were 3.8 to 11.9 pu higher in the test meal than in the diet with peas. The differences were significant (P < 0.05) for all indispensable AA. Other than lysine, glycine and proline, the AID of CP and AA were slightly higher, 0.1 to 4.3 pu, in the test meal than in the rapeseed meal diet. Of the indispensable AA, the differences were significant (P < 0.05) for arginine, leucine and phenylalanine. The AID of lysine was 10.9 pu lower (P < 0.05) in the test meal than in the rapeseed meal diet, 61.5 vs. 72.4%, indicating that guanidination of rapeseed meal was not uniform and random. The increase in the AID of CP and AA after guanidination may result from solubilisation of protein and degradation of antinutritional factors such as fiber, trypsin inhibitors and tannins.