Lysine restriction during grower phase on growth performance,blood metabolites,carcass traits and pork quality in grower finisher pigs

Abstract

The effects of lysine restriction during grower phase and realimentation during finisher phase on growth performance, nutrient digestibility, blood metabolites, carcass traits and pork quality were studied. Sixty-four pigs (two castrated males and two females per pen) weighing 34.34±5.22 kg were assigned to four dietary treatments. During grower (35–55 kg), pigs were fed isoenergetic lysine-restricted diets. The different lysine content of diets were 0.950 (NRC recommendation), 0.760, 0.665 and 0.570%, corresponding to lysine restriction of 20, 30 and 40%. Then all pigs were fed with common finisher 1 (55–85 kg) and 2 (85–115 kg) diets. Lysine restriction during the grower phase resulted in poor performance and lower concentration of blood metabolites but improved the nutrient digestibility and efficiency of lysine utilization. Compensatory growth response in terms of improved weight gain and feed efficiency was observed in pigs previously fed lysine-restricted diets during finisher 1, but the concentration of blood urea nitrogen and total protein were lower. No differences in growth performance, digestibility of nutrients and blood metabolites were noted during finisher 2. Lysine restriction of grower diets decreased the dressing percentage (quadratic, P=0.024), and protein content of longissimus muscle (linear P=0.034, and quadratic P=0.009). Thus, it could be concluded that pigs subjected to lysine restriction during grower phase exhibited compensatory growth responses in weight gain and improved efficiency of feed and lysine utilization for weight gain and lean accretion during finisher phase.     

Effects of ensiling cereal grains (barley,wheat, triticale and rye) on total and pre‐caecal digestibility of proximate nutrients and amino acids in pigs

Inclemency of weather frequently causes critical water contents in cereal grains above 15%. Ensiling in pre‐mature condition may be an alternative to other techniques of preservation. Aim of this study was to compare apparent total tract digestibility (D_t; barley, wheat, triticale, rye) of proximate nutrients and pre‐caecal digestibility (D_pc; barley, wheat) of amino acids (AA), respectively, from cereal grains in ensiled and almost dry condition. Moistly harvested cereal grains (67–73% dry matter) were milled through a 4‐mm sieve and ensiled with lactic acid bacteria (LAB, 3 × 10⁵ colony forming units/g Lactobacillus plantarum DSMZ 8862 and 8866). To investigate D_t, two trials were conducted with six Mini‐Lewe pigs and four German Landrace pigs, respectively. D_pc of AA was determined using four German Landrace pigs with ileo‐rectal anastomosis. D_t of proximate nutrients did not differ between cereal grains and their silages, except for ether extract, which was more digestible in ensiled than dry wheat, triticale and rye (p < 0.05). Lysine content was lower in ensiled than dry barley and wheat. In barley, ensiling was accompanied by reduced D_pc of lysine and histidine (p < 0.05). In wheat, ensiling increased D_pc of lysine, methionine, threonine and leucin (p < 0.05). Ensiling of pre‐mature cereal grains with LAB can serve as a reasonable storage alternative. However, as limited data are yet available, further research is required to understand completely the impact of ensiling on nutritional value as indicated, for example, by the lysine content and the D_pc of certain AA.     

Effect of a novel consensus bacterial 6-phytase variant in grower pigs fed corn-soybean meal-based diets formulated with a full nutrient matrix and no added inorganic phosphorus

The capacity of a novel consensus bacterial 6-phytase variant (PhyG) to entirely replace dietary inorganic phosphorus (Pi) source in grower pigs fed diets with reduction of calcium (Ca), net energy (NE), and digestible amino acids (AA) was evaluated, using growth performance and apparent total tract digestibility (ATTD) of nutrients as outcome measures. A total of 352 mixed-sex pigs (initial BW 23.4 kg) were randomized to 4 treatments, 8 pigs/pen, and 11 pens/treatment. Diets were corn-soybean meal-based and formulated by phase (grower 1, 25 to 50 and grower 2, 50 to 75 kg BW). The positive control diet (PC) provided adequate nutrients and a negative control diet (NC) was formulated without Pi (1.2 g/kg ATTD P) and reduced in Ca (-0.12 to -0.13 percentage points), NE (-32 kcal/kg), and digestible essential AA (-0.004 to -0.026 percentage points) vs. PC. Two further treatments comprised the NC plus 500 or 1,000 FTU/kg of PhyG. Data were analyzed by ANOVA, mean contrasts and orthogonal polynomial regression. Nutrient reductions in the NC reduced (P < 0.05) average daily gain (ADG) during grower 1 and overall (73 to 136 d of age), increased (P < 0.05) feed conversion ratio (FCR) during grower 1 and overall and tended to reduce (P < 0.1) average daily feed intake (ADFI) during grower 2 and overall, vs. PC. Phytase supplementation improved (P < 0.05) FCR during grower 1, ADG during grower 2 and overall, ATTD of DM and P, and tended to improve DE (P = 0.053) in a linear dose-dependent manner. PhyG at 1,000 FTU/kg resulted in growth performance (all measures, all phases) equivalent to PC. The findings demonstrate that PhyG at 1,000 FTU/kg totally replaced Pi in complex grower pig diets containing industrial co-products, compensated a full nutrient matrix reduction and maintained performance.     

Effect of dietary mannan-oligosaccharides on in vivo performance, nutrient digestibility and caecal content characteristics of growing rabbits

To evaluate the effect of mannan-oligosaccharides (MOS) on in vivo performance, nutrient digestibility, fermentation characteristics and caecal microbial populations of rabbits, 144 thirty-five days old hybrid Hyla were equally divided into three groups, one of which was fed the same diet without additives (control group), one with antibiotics (colistin sulphate, 144 mg/kg; tylosin, 100 mg/kg; oxytetracyclin, 1000 mg/kg) and one with MOS (1 g/kg of diet). Mortality rate, live weight, feed intake and feed conversion ratio were recorded up to 62 days of age. At 60 days nutrient digestibility was measured by acid insoluble ash method. The caecal content of 10 rabbits per group was collected at 62 days and analysed for volatile fatty acids production, ammonia content and microbial count. Rabbits from the control group had a significantly (p < 0.01) lower body weight at 62 days (1638.9 g vs. 1779.4 g and 1862.5 g, respectively for the control, MOS and antibiotic groups) while the antibiotic group showed a higher (p < 0.05) feed intake than the control group (127.9 g/day vs. 109.3 g/day). Rabbits from the MOS group had a higher apparent digestibility of cellulose (34.27% vs. 29.61% and 27.49%, respectively for the MOS, control and antibiotic groups) and, as a consequence a higher level of acetate in the caecal content (39.93 mmol/l vs. 34.21 mmol/l and 23.09 mmol/l, respectively for the MOS, control and antibiotic groups). Caecal microflora of the MOS group rabbits also had a higher fermentative activity in respect of protein source, as demonstrated by the higher productions of branched chain fatty acids. MOS and antibiotics significantly reduced the colonies of Coliformis (2.32 vs. 3.20 vs. 2.40 logCFU/g, respectively for the MOS, control and antibiotic groups, p < 0.01). Mannan-oligosaccharides at 1 g/kg of diet can be used as an alternative to antibiotics during the rabbit's growth period.     

A cross-sectional study of the prevalence and associated risk factors for bursitis in weaner, grower and finisher pigs from 93 commercial farms in England

A cross-sectional study of 93 farms in England was carried out to estimate the prevalence and associated risk factors for bursitis. A total of 6250 pigs aged 6–22 weeks were examined for presence and severity of bursitis. Details of pen construction, pen quality and farm management were recorded including floor type, presence of bedding, condition of the floor and floor materials. The prevalence of bursitis was 41.2% and increased with each week of age (OR 1.1). Two-level logistic regression models were developed with the outcome as the proportion of pigs affected with bursitis in a pen. Pigs kept on soil floors with straw bedding were used as the reference level. In comparison with these soil floors, bursitis increased on concrete floors where the bedding was deep throughout (OR 4.6), deep in part (OR 3.7), and sparse throughout (OR 9.0), part slatted floors (OR 8.0), and fully slatted floors (OR 18.8). Slip or skid marks in the dunging area (OR 1.5), pigs observed slipping during the examination of the pen (OR 1.3) and wet floors (OR 3.6) were also associated with an increased risk of bursitis. The results indicate that bursitis is a common condition of growing pigs and that the associated risk factors for bursitis were a lack of bedding in the lying area, presence of voids and pen conditions which increased the likelihood of injury.     

Prediction of protein and amino acid composition and digestibility in individual feedstuffs and mixed diets for pigs using near-infrared spectroscopy

Knowledge of the amounts and digestibility of amino acids in pig feedstuffs is essential for calculating the appropriate inclusion level in a complete diet. Wet chemical analysis and in vivo digestibility trials are time-consuming and costly and cannot be used for routine assessment. Near-infrared spectroscopy (NIRS) offers a rapid, cost effective and environmentally friendly method for evaluating feedstuffs. Calibrations models were developed using NIRS to predict the content of crude protein and 18 amino acids from a wide range of feedstuffs used in pig production (n = 607). The samples ranged from single feed ingredients (containing amino acids from 0.3 to 129.8 g/kg of dry matter) to feed mixtures (containing amino acids from 1.2 to 53.2 g/kg of dry matter). The predictive ability of the calibrations was tested with an independent dataset (n = 150) and with cross-validation. Furthermore, we compare these calibrations with calibrations developed on more narrowly defined groups of samples and with predictions from regression analysis of crude protein. The models were able to predict the concentrations of crude protein and 18 amino acids with good levels of precision and high coefficients of determination for calibration (RSQ ^CAL) from 0.91 to 0.99 and validation (RSQ^VAL) from 0.87 to 0.97. Calibration models were able to predict all amino acids except tryptophan and valine with greater accuracy than those from protein regression. We also developed calibration models to predict the apparent ileal and total tract digestibility of protein and amino acids. With the exception of tryptophan, RSQ values (>0.7) and standard error of cross validation (SECV) values (<5%) were obtained for the digestibility of most of the amino acids. In conclusion, NIRS can be used to predict crude protein and amino acid concentrations from a wide range of single ingredients and feed mixtures used for pig diets without separate models for each feedstuff. The digestibility of protein and amino acids can be predicted with an acceptable accuracy to be useful in formulating pig diets.     

Comparison of spray‐dried egg and albumen powder with conventional animal protein sources as feed ingredients in diets fed to weaned pigs

We evaluated the apparent (AID) and standardized ileal digestibility (SID) of amino acids (AA) in spray‐dried egg (SPE) and albumen powder (AP) compared with spray‐dried porcine plasma (SDPP), dried porcine solubles (DPS) and fish meal (FM). Additionally, the effects of these egg byproducts as a replacement for conventional animal proteins on the performance and nutrient digestibility of piglets were studied. In Exp. 1, six barrows fitted with ileal T‐cannulas were allotted to a 6 × 6 Latin Square design and fed six diets. The AID and SID of AA were generally higher in AP and FM (P < 0.01) than in the other protein sources. In Exp. 2, 150 piglets weaned at 21 days, were fed diets containing the five protein sources for 3 weeks. Weight gain of piglets fed SDPP was the highest among the treatments. Dry matter and protein digestibility for pigs offered SDPP were higher (P < 0.01) than those offered FM and DPS. AP decreased (P < 0.05) Escherichia coli counts in the cecum. DPS decreased (P < 0.05) serum diamine oxidase compared with SPE. In conclusion, AP and SPE are competitive with traditional animal protein sources and can be successfully fed to piglets without compromising performance.     

Body composition and muscle glycogen contents of piglets of sows fed diets differing in fatty acids profile and contents

To study the influence of sow dietary fat on piglet body characteristics, multiparous sows were allocated to one of four different dietary treatments: a conventional low fat (3%) diet (LF) and three high fat (6%) diets; high fat saturated (HFS), high fat oats (HFO), and high fat linseed (HFL). All sows were fed the allocated diet from weaning of the preceding litter until the day after farrowing. At farrowing, one liveborn piglet per litter (NB), was sacrificed and dissected immediately after birth. The heaviest (H) and the lightest (L) piglets in the litter were killed and dissected in the same manner at one day of age. Measurement of body length and circumference, organ weight, body chemical composition and muscle glycogen content were determined. Body measurements were adjusted to the mean body weight (1.67 kg). Dietary treatment did not have any significant influence on body components or carcass traits except for lung weight, being lower in HFO and HFL than in LF piglets. Piglet category affected almost all parameters considered, showing the lowest values for NB piglets, except for lung and circumference that were higher in NB than in L and H piglets; and length which was lower in NB than in L piglets. NB piglets had the highest amount of muscle glycogen content, no difference was found between H and L piglets. Dietary treatments influenced piglet chemical composition, showing the highest overall values of dry matter (DM), protein, and fat for the HFL piglets' carcasses. The present data provide additional information on the depletion of energy reserves; it would appear that sow dietary fat has relatively little effect on progeny since only body chemical composition was significantly influenced by HFL diet.     

Effects of brown rice particle size on energy and nutrient digestibility in diets for young pigs and adult sows

The objective of this study was to evaluate the effects of brown rice particle size on the apparent total tract digestibility (ATTD) of energy and nutrients in diets fed to pigs at four different stages and determine the optimal particle size (OPS) of brown rice for young pigs and adult sows. Eighteen weanling piglets (initial body weight (BW): 10.2 ± 0.4 kg), 18 growing barrows (initial BW: 35.6 ± 1.5 kg), 24 gestating sows (initial BW: 220 ± 2.8 kg), and 24 lactating sows (initial BW: 208 ± 3.8 kg) were allotted to 1 of 3 or 4 diets based on completely randomized design with six replicates per diet. Within each stage, brown rice‐soybean meal diets were formulated, and the only difference among diets was the brown rice used was ground to the specified particle size. Each stage lasted 19 days, including 7 days for cage adaptation, 7 days for diet adaptation, and 5 days for total feces and urine collection. For weanling and growing pigs, the results showed that pigs fed brown rice milled to 600 μm had a greater ATTD of dry matter (DM), gross energy (GE), and crude protein (CP) than pigs fed brown rice ground to 800 μm. However, there was no improvement in the ATTD of energy and nutrients for pigs fed brown rice milled to 600 μm versus 400 μm. The concentration of nitrogen (N) in feces significantly reduced (p < 0.01) as brown rice particle size decreased from 800 to 400 μm. However, there were no differences in phosphorus (P) output and absorbed P among diets. For gestating and lactating sows, a reduction in particle size from 1,000 to 800 μm significantly improved (p < 0.01) the ATTD of DM, GE, and CP in diets. However, there was also no improvement in the ATTD of energy and nutrients for pigs fed brown rice milled from 800 to 400 μm. In conclusion, considering the energy required for milling and nutrient digestibility, milling brown rice to 600 and 800 μm are recommended in diets for young pigs and adult sows, respectively. The OPS of brown rice for pigs at different physiological stages should be considered to economically and accurately formulate diets.     

The effect of amino acid restriction during the grower phase on compensatory growth, carcass composition and nitrogen utilisation in grower–finisher pigs

Three hundred and ninety six pigs weighing 42 kg (s.d. +/− 2.5 kg), (progeny of Landrace × Large White sows × Meatline boars) (216 boars and 180 females) were assigned to four dietary treatments to determine the effects of restricting dietary lysine during the grower period (approximately 42 to 63 kg) on nitrogen (N) intake, retention and excretion during the finisher period (approximately 63 kg to slaughter at 94 kg). Two experiments, a performance experiment (nine replicates/treatment) and a N balance experiment (four replicates/treatment) were carried out. The experimental treatments were (1) 1.25% lysine from d 0 to d 28 and 1.05% lysine from d 29 to slaughter (HM), (2) 1.05% lysine from d 0 to slaughter (MM), (3) 0.85% lysine from d 0 to d 28 and 1.05% lysine from d 29 to slaughter (LM) and (4) 0.85% lysine from d 0 to slaughter (LL). All diets were pelleted and formulated to contain 13.8 MJ DE/kg. The pigs were group fed in mixed sex pens using single space feeders (11 pigs/feeder, 6 boars and 5 females). In the N balance experiment, sixteen entire male pigs, after 16 days on the diets were placed individually in metabolism crates and urine and faeces were collected. The pigs offered the 0.85% lysine diets during the grower period had a lower average daily gain (ADG) and a poorer feed conversion ratio (FCR) than the pigs offered 1.25% and 1.05% lysine diets (P < 0.05). During the early finisher period (days 29–42) and overall finisher period (days 29–56) pigs on treatment LM had a higher ADG (P < 0.01) and a better FCR (P < 0.05) than pigs on treatment LL. Pigs on treatment LM also had a better FCR than pigs on treatment HM and MM (P < 0.05) during the early finisher period. Pigs on treatment LM had a significantly (P < 0.05) higher lean meat proportion than pigs on treatment LL. During the grower N balance, pigs on the 0.85% lysine diets (treatments LM and LL) had lower N intakes (P < 0.001), N excretions (P < 0.001) and a higher (P < 0.001) nitrogen utilisation than pigs on treatments MM and HM. During the finisher N balance, pigs on treatment LL had a lower N intake (P < 0.001), N excretion (P < 0.01) and N retention (P < 0.05) than pigs on all other treatments. In conclusion, restricting dietary lysine during the grower period reduced growth rate but resulted in a more efficient growth during the early finisher period once dietary lysine was restored.     

Comparison of spray-dried blood meal and blood cells in diets for nursery pigs

We used a total of 680 pigs to compare spray-dried blood meal and blood cells in nursery diets. In Exp. 1, 350 barrows (17 +/- 2 d of age at weaning) were used to compare three levels of spray-dried blood meal or blood cells (2.5, 5.0, and 7.5%) in the diet fed from d 5 to 19 postweaning (6.6 to 9.9 kg). Inclusion of either blood product improved ADG (P < 0.005) and G:F (P < 0.001) compared to pigs fed the control diet without added blood products. However, pigs fed spray-dried blood meal had greater ADG (P < 0.001), ADFI (P < 0.04), and G:F (P < 0.001) from d 0 to 7 compared to those fed blood cells. The greatest differences observed between the two blood products occurred at the 5 and 7.5% inclusion levels. No differences (P > 0.05) in growth performance were detected between the two blood products from d 7 to 14. In Exp. 2, 380 barrows (initial BW of 10.7 kg and 41 +/- 2 d of age) were used to determine lysine bioavailability of spray-dried blood meal and blood cells via the slope ratio procedure. With G:F ratio as the response criterion, blood meal and blood cells had similar lysine bioavailability relative to crystalline lysine. These experiments indicate that both blood products had similar lysine bioavailability, and that pigs fed spray-dried blood meal had greater performance during the initial 7 d (d 5 to 12 after weaning). However, as the pigs became heavier, there were no differences observed in performance of pigs fed either blood meal or blood cells.     

Comparison of wheat gluten and spray-dried animal plasma in diets for nursery pigs

Five experiments were conducted to determine the effects of different wheat gluten (WG) sources (Source 1 = enzymatically hydrolyzed, Source 2 = nonmodified ring-dried, Source 3 = spray-dried, and Source 4 = flash-dried) on growth performance of nursery pigs compared with soybean meal (SBM), spray-dried animal plasma (SDAP), or other specialty protein sources. In Exp. 1, pigs (n = 220, initially 6.1 +/- 2.5 kg) were fed a control diet containing (as-fed basis) 6% SDAP or WG Source 1 or 2. The WG and l-lysine*HCl replaced 50 or 100% of the SDAP. From d 0 to 21, increasing WG (either source) decreased ADG and ADFI (linear, P < 0.01), but improved (linear, P < 0.02) G:F. In Exp. 2, pigs (n = 252, initially 6.2 +/- 3.0 kg) were fed a negative control diet containing no SDAP or WG, diets containing (as-fed basis) 9% WG Source 1 or 5% SDAP, or combinations of WG and SDAP where WG and l-lysine*HCl replaced 25, 50, or 75% of SDAP. From d 0 to 14, pigs fed increasing WG had decreased ADG (linear, P < 0.05). In Exp. 3, pigs (n = 240, initially 7.0 +/- 2.5 kg) were fed a negative control diet, a diet containing (as-fed basis) either 3, 6, 9, or 12% WG Source 3, or a positive control diet containing 5% SDAP. The diets containing 9% WG and 5% SDAP had the same amount of SBM. From d 0 to 7, pigs fed 5% SDAP had greater (P < 0.04) ADG than pigs fed the diet containing 9% WG. From d 0 to 14, increasing WG had no effect on ADG, ADFI, or G:F. In Exp. 4, pigs (n = 200, initially 6.0 +/- 2.4 kg) were fed a negative control diet, the control diet with (as-fed basis) 4.5 or 9.0% WG Source 1, or the control diet with 2.5 or 5.0% SDAP. Diets containing WG and SDAP had similar SBM levels. From d 0 to 7 and 0 to 14, increasing SDAP tended to improve (linear, P < 0.06) ADG, but increasing WG had no effect. In Exp. 5, 170 barrows and gilts (initially 7.5 +/- 2.8 kg) were used to determine the effects of WG Source 1 and 4 compared with select Menhaden fish meal or spray-dried blood cells and a negative control diet (SBM) on the growth performance of nursery pigs from d 5 to 26 postweaning (d 0 to 21 of experiment). No differences were found in ADG or G:F, but pigs fed the diet containing (as-fed basis) 2.5% spray-dried blood cells had greater ADFI than pigs fed the negative control from d 0 to 21. Wheat gluten source had no effect on ADG, ADFI, or G:F. The results of these studies suggest that increasing WG in diets fed immediately after weaning did not improve growth performance relative to SBM or SDAP.     

生长猪低磷日粮添加植酸酶和有机酸以及维生素D_3的研究

本试验通过添加植酸酶、有机酸(柠檬酸、抗坏血酸)和维生素D3、木聚糖酶来减少无机磷的添加量,提高饲料中植酸磷的利用率,降低磷的排泄量。选择30 kg左右的"斯格"纯种猪70头,随机分成7组:常磷组、低磷日粮组(NC)、NC+600 U/kg植酸酶组、NC+600 U/kg植酸酶+10 g/kg的柠檬酸、NC+600 U/kg植酸酶+10 g/kg的柠檬酸+200 mg/kg抗坏血酸、NC+600 U/kg植酸酶+10 g/kg的柠檬酸+200 mg/kg抗坏血酸+100μg/kg的维生素D3、不添加磷酸氢钙。所有日粮中都添加50 mg/kg木聚糖酶。结果表明:低磷日粮添加植酸酶、有机酸(柠檬酸、抗坏血酸)和维生素D3,平均日采食量无显著影响(P0.05),日增重显著提高(P0.05),料重比显著降低(P0.05);养分消化率均显著提高;血液指标着中,白蛋白显著降低(P0.05),碱性磷酸酶、总蛋白、谷草、谷丙转氨酶无影响(P0.05)。     

加工工艺和酶技术对猪和家禽高纤维日粮消化率的影响

在常用的重量法、纤维分析法的纤维馏分中,多糖的潜在转移阻碍了对非淀粉多糖消化效果的评价,在实际应用过程中应谨慎解释加工技术或酶处理对粗纤维、中性洗涤剂纤维或酸性洗涤剂纤维消化率的影响,而不是非淀粉多糖消化率的体内研究结果。非淀粉多糖组分组成及其组分消化率的详细信息有助于识别和理解加工过程中发生的变化。因此,本文综述了加工工艺对猪、禽非淀粉多糖理化性质的影响及其对非淀粉多糖降解的影响。     

A cross-sectional study of the prevalence and associated risk factors for capped hock and the associations with bursitis in weaner, grower and finisher pigs from 93 commercial farms in England

The prevalence of capped hock in 5601 post-weaning pigs from 93 pig farms in England was 17.2%. The prevalence increased with age. Once adjusted for age, the lowest prevalence of capped hock was observed in pigs kept on soil floors (usually covered with deep straw bedding). There was no significant increase in the risk of capped hock in pigs kept on solid concrete floors with deep straw bedding. However, pigs kept on solid concrete with some, or the entire pen, sparsely bedded and pigs kept on partially or fully slatted floors had an approximately threefold increased risk of capped hock. This did not vary significantly between these four floor types. This was in contrast to the associated risks for bursitis in the same pigs, where as the floor went from highly resilient (straw and solid floors) to hard and perforated (fully slatted) the risk of bursitis increased in a similar way to a dose response. No other variables that were measured were associated with a change in risk for capped hock, while observation of pigs slipping or slip marks and wet, dirty and worn pens were also associated risks for bursitis. These results indicate that capped hock and bursitis are both affected by exposure to floors, but in different ways. The prevalence of capped hock was associated only with floor hardness, with deep straw protecting the pigs, while bursitis was associated with both changes in bedding depth (hardness), floor material (soil versus concrete) and floor construction (solid versus slatted floors) and in factors associated with locomotion (slipping and slip marks). These results indicate that the aetiology of capped hock and bursitis might differ.     

Intrinsic phytase in hybrid rye increases the digestibility of phosphorus in corn and soybean meal in diets fed to growing pigs

An experiment was conducted to test the hypothesis that inclusion of hybrid rye in diets containing corn and soybean meal (SBM) without or with microbial phytase improves the apparent total tract digestibility (ATTD) and the standardized total tract digestibility (STTD) of P because of the intrinsic phytase activity in hybrid rye. Forty-eight growing barrows (initial body weight: 39.5 ± 7.7 kg) were allotted to six diets. A basal diet containing corn and SBM; a rye-based diet; and a diet containing corn, SBM, and rye were formulated. Each diet was formulated without and with microbial phytase (500 units/kg of diet) for a total of six diets. Fecal samples were collected for 4 d following a 5-d adaptation period according to the marker-to-marker procedure. Results indicated that no interactions between diets and concentration of phytase were observed for any of the response criteria measured. The ATTD and STTD of P and the ATTD of Ca differed (P < 0.05) among diets, but regardless of diet, the concentration of P in feces was reduced (P < 0.05) by adding microbial phytase to the diets. As a consequence, microbial phytase increased (P < 0.05) ATTD and STTD of P, and the ATTD of Ca was also increased (P < 0.05) by the use of microbial phytase. Measured values for the ATTD and STTD of P in the diets containing corn, SBM, and hybrid rye without or with phytase were greater (P < 0.05) than values that were predicted based on the ATTD and STTD of P for the corn–SBM and the hybrid rye diet. The observation that STTD predicted from the individual ingredients underestimated the STTD of P in the mixed diet indicates that the intrinsic phytase in hybrid rye resulted in increased digestibility of the P in the corn and SBM included in the corn–SBM–hybrid rye diet. In conclusion, microbial phytase increased the ATTD and STTD of P and the ATTD of Ca regardless of feed ingredients used in diets fed to pigs. In addition, the intrinsic phytase from hybrid rye increased the ATTD and STTD of P in corn and SBM.     

Digestion and deposition of individual fatty acids in growing-finishing pigs fed diets containing either beef tallow or sunflower oil

The apparent digestibility and deposition in carcass of individual dietary fatty acids (FA) were determined in growing-finishing pigs fed diets containing either beef tallow or sunflower oil. The beef tallow was rich in saturated FA (SFA) and the sunflower oil had a high content of polyunsaturated FA (PUFA). A total of 39 barrows was used. The experimental diets contained 5% (w/w) of the variable fat source and were fed ad libitum . The dietary fat type had no effect (p > 0.05) on growth performance, even though the apparent digestibilities of crude fat and crude protein were higher (p < 0.05) in the animals fed sunflower oil. The pigs fed the sunflower oil diet showed higher apparent digestibilities (p < 0.05) of the sum of SFA, monounsaturated FA (MUFA) and PUFA, but had a lower digestibility (p < 0.05) of stearic acid. The intakes of individual digestible FA were derived feed intake data, FA contents of the diets and the digestibility of individual FA. For the entire feeding period of 13 weeks, the ratio of deposition in carcass to intake of digestible FA was increased (p < 0.05) for palmitic and stearic acid in the pigs fed sunflower oil, but the ratios for oleic acid and linoleic acid were decreased (p < 0.001). In the pigs fed sunflower oil instead of beef tallow, the deposition:intake ratio was raised for the SFA (p < 0.001), but diminished for the MUFA (p < 0.05). The calculated minimum de novo synthesis of SFA was increased (p < 0.05) and that of MUFA decreased (p < 0.05) in the pigs fed sunflower oil. It is concluded that the feeding of a diet with sunflower oil instead of beef tallow improved apparent digestibility of SFA, MUFA and PUFA, increased the deposition:digestible intake ratio for SFA, but lowered that for MUFA and PUFA.     

Intake and apparent digestibility of hay or hay plus concentrate diets determined in horses by the total collection of feces and n-alkanes as internal markers

The apparent digestibility of hays plus two commercial mixed feeds containing about 14% and 11.8% crude fiber (CF), respectively as feeds was determined by means of two in vivo digestibility trials, each performed on 4 or 5 saddle horses weighing on average about 550 and 535 kg, respectively, over a 6 day feces total collection period with a previous 14 day adaptation period. The diets were based on a first cut meadow hay – whose digestibility was estimated in each trial – and different percentages of the mixed feeds at a feeding level close to maintenance. The two mixed feeds were rich respectively in a by-product from the citrus fruit industry (citrus pulp) and in a by-product from the apple fruit industry (apple pectin pulp). The forage to concentrate ratio was, respectively, 50:50, 75:25 and 100:0 on a dry matter basis (Diets 1, 2 and 3) in the first trial and, 50:50 and 100:0 (Diets 4 and 5) in the second trial.

The apparent digestibility of the dry matter, organic matter, gross energy, and crude protein was measured by the ingesta/excreta procedure and using the most abundant n-alkanes (C₂₇, C₂₉, and C₃₁) as internal markers for all the rations and the hays.

No differences were found among the digestibility coefficients obtained by the total collection method or using the different n-alkanes.

The use of n-alkanes for digestibility determinations in horses is neither precise nor accurate, but can be advised for free ranging animals, when the total collection of feces is impossible. Taking into account that the accuracy of this later method is comparable, we suggest selecting n-alkanes with a high concentration and the highest fecal recovery; C₂₉ and C₃₁ n-alkanes (the first in particular) resulted to be the best choice.     

玉米赤霉烯酮污染日粮添加膨润土对断奶仔猪生长性能、养分利用率及生殖器官发育的影响

文章旨在评估玉米赤霉烯酮污染日粮添加膨润土对断奶仔猪生长性能、养分利用率、血清生化指标及生殖器官发育的影响。试验1选择28 d断奶仔猪[(10.00±0.85)kg]960头,随机分为8组,每组4个重复,每个重复30头。试验1日粮采用4(玉米赤霉烯酮水平:0、0.3、0.6和0.9 mg/kg)×2膨润土(0、2或0.5或1 g/kg),试验阶段28～56 d。试验2选择56 d仔猪[(27.00±1.40)kg]480头,分组同试验1。试验2日粮玉米赤霉烯酮水平同试验1,膨润土水平为0或2 g/kg,试验阶段57～75 d。结果显示:随着日粮玉米赤霉烯酮水平的升高,日增重和饲料报酬显著线性降低(P <0.05)。日粮添加膨润土显著提高了28～56 d断奶仔猪饲料报酬(P <0.05)。日粮添加2 g/kg膨润土显著提高了57～75 d断奶仔猪的平均日增重(P <0.05)。日粮玉米赤霉烯酮显著降低了采食量和饲料报酬(P <0.05),但添加膨润土显著提高了饲料报酬(P <0.05)。随着日粮玉米赤霉烯酮水平的升高,干物质和氮表观消化系列表现为显著的线性降低(P <0.05)。28 d断奶仔猪阴户宽度、长度和面积随着日粮玉米赤霉烯酮水平的升高表现为显著的线性升高(P <0.05)。玉米赤霉烯酮污染日粮添加2 g/kg膨润土显著降低了阴户长度和面积(P <0.05)。日粮添加膨润土显著提高了2和4周龄仔猪粪中乳酸杆菌含量(P <0.05),显著降低大肠杆菌含量(P <0.05)。结论 :断奶仔猪采食较低水平玉米赤霉烯酮污染日粮会降低营养物质消化率,诱发氧化应激,使生长性能下降。添加膨润土后可以缓解采食玉米赤霉烯酮污染日粮对仔猪的毒副作用。