Lysolecithin,but not lecithin,improves nutrient digestibility and growth rates in young broilers

ABSTRACT

1. The potential of lecithin and lysolecithin to improve lipid digestion and growth performance was investigated in three experiments: 1. an in vitro model that mimics the intestinal conditions of the chick, 2. a digestibility trial with chicks (5–7 days of age), and 3. a performance trial until 21 days of age.

2. In experiment 1, palm oil (PO), palm oil with lecithin (PO+L), and palm oil with lysolecithin (PO+LY) were subjected to in vitro hydrolysis and applied to Caco-2 monolayers to assess lipid absorption.

3. The in vitro hydrolysis rate of triglycerides was higher in PO+LY (k = 11.76 × 10³/min) than in either PO (k = 9.73 × 10³/min) or PO+L (k = 8.41 × 10³/min), and the absorption of monoglycerides and free fatty acids was highest (P < 0.01) for PO+LY. In experiment 2, 90 broilers were assigned to three dietary treatments: a basal diet with 4% palm oil, and the basal diet supplemented with either 250 ppm lecithin or lysolecithin.

4. ATTD of crude fat was higher in broilers supplemented with lysolecithin, but was lower in broilers supplemented with lecithin. DM digestibility and AMEn in birds supplemented with lysolecithin were significantly higher (3.03% and 0.47 MJ/kg, respectively).

5. In experiment 3, 480 broilers were randomly allocated to four dietary treatments: basal diet with soybean oil (2%), basal diet with lecithin (2%), soybean oil diet with 250 ppm lysolecithin, or lecithin oil diet with 250 ppm lysolecithin.

6. Lecithin diets significantly reduced weight at day 10 and 21 compared with soybean oil. However, the addition of lysolecithin to lecithin-containing diets significantly improved bird performance.

7. The results of these studies showed that, in contrast to lecithin, lysolecithin was able to significantly improve the digestibility and energy values of feed in young broilers.     

Nutrient digestibility and evaluation of protein and carbohydrate fractionation of citrus by‐products

The protein and carbohydrate fractionation and nutrient digestibility of citrus by‐products were determined. Ruminal, intestinal and total tract CP disappearance values were measured by a modified three‐step (MTSP) method and in vitro CP disappearance method (IVCP). Test feeds were orange pulp (OP), lime pulp (LP), lemon pulp (LEP), grapefruit pulp (GP), sweet lemon pulp (SLP), bitter lemon pulp (BLP), bergamot orange pulp (BP) and tangerine pulp (TP). The rumen undegradable protein (RUP) fractions of the feedstuffs were obtained by ruminal incubation in three cannulated wethers and incubation in protease solution (protease type xiv, Streptomyces griseus). The data were analysed using completely randomized design. There were significant differences between the tested feeds in protein fractions and acid detergent insoluble nitrogen (ADIN; C fraction) was highest in GP (14.56%) (p < 0.001). For carbohydrate fraction, the highest C fraction was also observed in GP (2.67%) and in relation to the other citrus pulps (p < 0.001). Ruminal CP disappearance was highest in OP (71.89%) (p < 0.001). The level of post‐ruminal CP disappearance, measured by MTSP, was highest for BP (34.94%) (p < 0.001). The highest in vitro dry matter digestibility (IVDMD) was found for TP (80.44%) followed by that estimated for BP (78.38%) (p < 0.001). The estimated metabolizable energy (MJ/kg DM) varied from 9.77 for LP to 12.91 for BP. Tangerine pulp had the highest true rumen digestibility (TRD) (p < 0.001). According to the results, it could be concluded that citrus by‐products have high nutritive value and also, the in vitro techniques can be easily used to determine of the nutritive value of citrus by‐products.     

Effect of feeding dried distillers' grains with solubles on milk yield and milk composition of cows in mid‐lactation and digestibility in sheep

We evaluated the effect of three sources of dried distillers' grains with solubles (DDGS) in diets of mid‐lactating dairy cows on milk production and milk composition and on digestibility in sheep. DDGS from wheat, corn and barley (DDGS₁), wheat and corn (DDGS₂) and wheat (DDGS₃) were studied and compared with a rapeseed meal (RSM). RSM and DDGS were characterized through in situ crude protein (CP) degradability. Nutrient digestibility was determined in sheep. Twenty‐four multiparous cows were used in a 4 × 4 Latin square design with 28‐day periods. Treatments included total mixed rations containing as primary protein sources RSM (control), DDGS₁ (D1), DDGS₂ (D2) or DDGS₃ (D3). RSM contained less rapidly degradable CP (fraction a), more potentially degradable CP (fraction b) and more rumen undegradable CP (UDP) than the three DDGS. In vivo digestibility of RSM organic matter was similar to DDGS. Calculated net energy for lactation (NE_L) was lower for RSM (7.4 MJ/kg DM) than for DDGS, which averaged 7.7 MJ/kg DM. Cows' dry matter intake did not differ between diets (21.7 kg/day). Cows fed D1 yielded more milk than those fed D3 (31.7 vs. 30.4 kg/day); no differences were found between control and DDGS diets (31.3 vs. 31.1 kg/day). Energy‐corrected milk was similar among diets (31.2 kg/day). Diets affected neither milk fat concentration (4.0%) nor milk fat yield (1.24 kg/day). Milk protein yield of control (1.12 kg/day) was significantly higher than D3 (1.06 kg/day) but not different form D1 and D2 (1.08 kg/day each). Feeding DDGS significantly increased milk lactose concentration (4.91%) in relation to control (4.81%). DDGS can be a suitable feed in relation to RSM and can be fed up to 4 kg dry matter per day in rations of dairy cows in mid‐lactation. However, high variation of protein and energy values of DDGS should be considered when included in diets of dairy cows.     

The effect of short-term phytase supplementation on the apparent total tract digestibility of calcium and phosphorus and the reproductive performance of late gestation and lactating sows fed diets without mineral phosphorus

The objective of this study was to measure apparent total tract digestibility (ATTD) of Ca and P as well as reproductive performance in late gestation and lactating sows supplemented with a novel phytase and to compare the response to phytase supplementation between late gestation and lactating sows. A total of 45 late gestation sows and 45 lactating sows were used in experiments 1 and 2, respectively, in a completely randomized design. The sows were provided with a control diet or the control diet supplemented with 187.5 or 375 FYT phytase/kg feed for 10 days. The diets were prepared according to the formulas in use for production but without any inorganic P supplement. Titanium dioxide was included at 3 g/kg feed as an indigestible marker. Each dietary treatment was replicated with 15 sows individually housed in farrowing stalls. The sows were allowed to adapt to the experimental diets for 5 days before a 5-d fecal collection by grab sampling, and the performance of the sows and their litters were measured until weaning. The results showed that the ATTD of Ca increased linearly (P < 0.001), while the ATTD of P increased both linearly and quadratically (P < 0.01) with increasing supplementation of phytase in both late gestation and lactating sows. There was no significant effect of phytase on the ATTD of dry matter, crude protein, and gross energy, and the performance of the sows and their progenies. The phytase added at 187.5 and 375 FYT/kg feed released 0.07% and 0.10% digested P, respectively, in late gestation sows, which compared with 0.09% and 0.12% digested P in lactating sows. In conclusion, a novel phytase at 187.5–375 FYT/kg feed could release 0.07–0.12% digestible P for sows. It appeared that using the P digestibility values of feed ingredients listed by NRC to formulate a diet for sows might overestimate dietary P supply and a greater response to phytase supplementation could be expected in lactating sows than in late gestation sows.     

Demonstration of uniformity of calcium absorption in adult dogs and cats

A meta‐analysis was conducted to understand quantitative aspects of calcium (Ca) and phosphorus (P) absorption in adult dogs and cats. 34 studies in dogs and 14 studies in cats met the criteria for inclusion in the meta‐analysis. Intake and faecal excretion values of Ca and P were subjected to a modified Lucas test and subsequent regression analyses. According to the current scientific consensus, Ca true digestibility (absorption) should increase at low Ca intake and decrease at high Ca intake. If true, this should result in a nonlinear relationship between the percentage of Ca excreted and dietary Ca intake. The present meta‐analysis showed a highly significant linear relationship (p < 0.0001) between Ca intake and Ca excretion suggesting a lack of systematic quantitative adaptation in true Ca digestibility. This finding suggests either that the time period covered by standard digestion trials is too short to induce adaptation mechanisms or that dogs and cats at maintenance will not efficiently alter quantitative Ca absorption percentage according to the amount ingested. If the latter is true, a dietary Ca supply differing greatly from the recommended dietary intake might impair the health of cats and dogs when fed long term. The data plots for P intake and faecal excretion were less uniform suggesting other factors not just dietary intake influence faecal P excretion. In adult cats, the dietary Ca:P ratio strongly influenced the true digestibility of P, whereas this effect was less marked in adult dogs. Faecal P excretion was significantly correlated to faecal Ca excretion in both species (p < 0.0001), and surprisingly, the level of P intake did not appear to be an important determinant of true digestibility of P.     

A comparative meta‐analysis on the relationship of faecal calcium and phosphorus excretion in mammals

To investigate the relationship between faecal calcium (Ca) and phosphorus (P) excretion in different mammalian species, a meta‐analysis on digestibility data derived from the literature was conducted. Seventy‐three studies on carnivores, omnivores, large and small hindgut fermenters, ruminants and hippos (a total of 21 mammalian species, precondition for inclusion dietary Ca/P ratio 1.5/1 – 3.0/1) were analysed for Ca and P digestibility. Dietary Ca/P ratios were lower than faecal Ca/P ratios in carnivores, omnivores, ruminants and hippos. In hindgut fermenters, dietary Ca/P ratios were higher than faecal Ca/P ratios, indicating higher intestinal Ca absorption in these species. In all species investigated, there was a significant positive relationship between Ca intake and faecal Ca excretion and between P intake and faecal P excretion. In the biologically relevant range, these equations predicted lower faecal Ca losses in hindgut fermenters than ruminants, for faecal P vice versa. In all species, faecal Ca and P excretion correlated significantly. In carnivores, this highly linear correlation was exceptionally strong (R² = .92). Yet, the linearity of the correlation was questionable in omnivores and ruminants. Possibly, the strong linear correlation of faecal Ca and P excretion in carnivores is due to the formation of insoluble Ca/P complexes in their relatively short and simple gastrointestinal tract. Another hypothesis is that in carnivores, Ca homeostasis relies on modifying bone turnover to a higher degree than on changes in intestinal Ca absorption. For the formation of bone matrix, a constant ratio of Ca and P absorption is of advantage.     

Influence of feeding thermally peroxidized lipids on growth performance, lipid digestibility,and oxidative status in nursery pigs

Three experiments were conducted to evaluate oil source and peroxidation status (experiment 1) or peroxidized soybean oil (SO; experiments 2 and 3) on growth performance, oxidative stress, and digestibility of dietary ether extract (EE). In experiment 1, palm oil (PO), poultry fat (PF), canola oil (CO), and SO were evaluated, while in experiments 2 and 3, only SO was evaluated. Lipids were either an unheated control (CNT) or thermally processed at 90 °C for 72 hr, being added at 10%, 7.5%, or 3% of the diet in experiments 1, 2, and 3, respectively. In experiment 1, 288 pigs (body weight, BW, 6.1 kg) were fed 1 of 8 factorially arranged treatments with the first factor being lipid source (PO, PF, CO, and SO) and the second factor being peroxidation status (CNT or peroxidized). In experiment 2, 216 pigs (BW 5.8 kg) were fed 1 of 6 treatments consisting of 100%, 90%, 80%, 60%, 20%, and 0% CNT SO blended with 0%, 10%, 20%, 40%, 80%, and 100% peroxidized SO, respectively. In experiment 3, 72 pigs (BW 5.8 kg) were fed either CNT or peroxidized SO. Pigs were fed 21 d with feces collected on day 12 or 14 and pigs bled on day 12 blood collection. In experiment 1, an interaction between oil source and peroxidation status was observed for averaged daily gain (ADG) and average daily feed intake (ADFI; P = 0.10) which was due to no impact of feeding pigs peroxidized PO, PF, or SO on ADG or ADFI compared with feeding pigs CNT PO, PF, or SO, respectively; while pigs fed peroxidized CO resulted in reduced ADG and ADFI compared with pigs fed CNT CO. There was no interaction between oil source and peroxidation status, and no lipid source effect on gain to feed ratio (GF; P ≥ 0.84), but pigs fed the peroxidized lipids had a lower GF compared with pigs fed the CNT lipids (P = 0.09). In experiment 2, feeding pigs diets containing increasing levels of peroxidized SO resulted in reduced ADG (quadratic, P = 0.03), ADFI (linear, P = 0.01), and GF (quadratic, P = 0.01). In experiment 3, feeding peroxidized SO at 3% of the diet reduced ADG (P = 0.11) and ADFI (P = 0.13), with no observed change in GF (P = 0.62). Differences in plasma protein carbonyls, glutathione peroxidase, and vitamin E due to feeding peroxidized lipids were inconsistent across the 3 experiments. Digestibility of dietary EE was reduced in pigs fed peroxidized PO or SO (P = 0.01, experiment 1) and peroxidized SO in experiments 2 and 3 (P ≤ 0.02). In conclusion, the peroxidation status of dietary lipids consistently affects growth performance and EE digestibility but has a variable effect on measures of oxidative stress.     

Effect of captivity and mineral supplementation on body composition and mineral status of mustached bats (Pteronotus parnellii rubiginosus)

We investigated the whole-body crude nutrient (fat, protein, ash) and mineral (Ca, P, Mg, Na, K) composition of mustached bats of three different groups: animals from the wild (n = 6), and animals from captivity on an unsupplemented feeding regime of mealworms (n = 7), and on a feeding regime in which the mealworms were kept on a mineral substrate prior to feeding (n = 6). It was shown that mealworms from the mineral substrate had higher Ca contents than mealworms from the conventional substrates. In an earlier study, differences in bone mineral density had been found between the groups. These differences, however, were not reflected in differences in whole-body composition. Captive animals showed a larger variation in body weight and fat content, indicating potential shortcomings of the dietary and husbandry regime.     

Influence of cellulose fibre length on faecal quality,mineral excretion and nutrient digestibility in cat

In dogs, faeces quality and nutrients digestibility were affected by different types of cellulose ( Wichert et al., 2002 ). In this study, it was investigated whether there are comparable effects of cellulose type in cats. Seven adult, healthy cats were fed a moist commercial complete cat food with three different cellulose type added at a level of 4% for a 1 week period. Faeces quality was between 1 and 3 on the scale used from 1 to 5. The addition of long fibre cellulose resulted in significantly firmer faeces. Addition of cellulose decreased the digestibility of dry matter and energy, whereas the impact on protein and fat digestibility was not significant. The type of cellulose affected faecal bulk and faecal water excretion. Faecal excretion of sodium and potassium was exponentially correlated to faecal water, faecal bulk and to a lesser extent to faecal dry matter excretion. Faecal calcium, magnesium and phosphorus excretion showed an exponential correlation to faecal dry matter excretion. A weaker correlation existed in all three elements to faecal bulk, whereas the effect of faecal water excretion was small. Results suggest a remarkable likeness between cats and dogs with regard to the digestive physiology of major minerals.     

Nutrient digestibility and energy value of sheep rations differing in protein level, main protein source and non-forage fibre source

Two in vivo digestion trials were conducted to evaluate the effects of diet's crude protein (CP) level, N degradability, and non-forage fibre source (NFFS) on nutrient digestibility and energy value of sheep rations. In each trial, rams were fed four isocaloric and isofibrous rations, differing in main protein and/or NFFS source. At the first trial, mean CP/metabolizable energy (ME) ratio of the diets was 17 g/MJ ME and at the second trial, 13 g/MJ ME. At both trials, the first ration contained cotton seed cake (CSC) and wheat bran (WB), the second CSC and corn gluten feed (CGF), the third corn gluten meal (CGM) and WB and the fourth CGM and CGF. Data of both trials were analysed in common as 2 x 2 x 2 factorial experimental design. Low N degradability (CGM) had positive effect on CP, neutral detergent fibre (NDF) and acid detergent fibre (ADF) digestibility of the ration. Those results suggest that an increase in rumen undegradable protein (RUP) content does not negatively affect nutrient digestibility of sheep rations. Corn gluten feed significantly elevated crude fibre (CF) digestibility, in comparison with WB. Rations having high CP/ME ratio had higher digestibility of CP in comparison with those having low CP/ME ratio; the opposite was true for ether extract, CF, NDF and ADF digestibilities. CP level x N degradability interaction negatively affected energy value of the rations that had high CP level and high N degradability. Former suggest that when CP content is high then N degradability should be low otherwise ration's ME is negatively affected. CP digestibility and coefficient q of the rations containing WB and having high N degradability (N degradability x NFFS interaction) were the lowest suggesting that the combination of CSC and WB negatively affected CP digestibility and energy value of the ration. This could be explained by a reduced microbial CP synthesis, or lower RUP digestibility or both.     

日粮添加共轭亚油酸钙盐和葵花油对奶牛产奶性能及饲料消化率的影响

试验研究了奶牛日粮中添加过瘤胃共轭亚油酸(Ca-CLA),同时添加葵花油对奶牛生产性能和饲料利用率的影响。选择健康、泌乳月份与产奶量相近的多胎荷斯坦泌乳牛20头,随机分成5组,每组4头。对照组(A组)基础日粮为60%粗饲料(苜蓿、羊草、青贮)和40%精料(以DM为基础),处理组在对照组日粮基础上每天每头牛分别添加Ca-CLA100g(B组)、葵花油350g(C组)、Ca-CLA100g+葵花油350g(D组)、Ca-CLA50g+葵花油175g(E组)。试验共进行52d。结果表明:C组产奶量较对照组差异不显著(P>0.05),B、D、E组产奶量较对照组都分别显著提高2.20%、9.95%、11.16%(P<0.05);B、C、D、E组牛奶的乳脂率较对照组都分别显著降低15.00%、6.74%、21.74%、14.35%(P<0.05)。与对照组相比,B组显著提高饲料中EE、CP、NDF、ADF消化率;C组除脂肪外其它营养成分消化率有降低的趋势但差异不显著;D、E组除脂肪消化率显著提高外,其它营养成分消化率差异不显著。     

椰子粕、棕榈粕和木薯对猪磷表观消化率的影响

文章旨在评估分别以椰子粕、棕榈粕和木薯为主的日粮对生长猪磷表观消化率的影响。试验将平均体重为(40.2±0.58)kg的24头公猪随机分为4组,每组3个重复,每个重复2头猪。其中1组是日粮以玉米淀粉、蔗糖和明胶为主要原料的无磷日粮,测定了磷的基础内源损失,其他组日粮中含有40%的椰子粕、棕榈粕或木薯。试验共进行21 d,包括3个周期,每个周期分为3 d适应期,4 d样品采集期。结果:化学成分结果显示,椰子粕和棕榈粕的粗蛋白质、粗脂肪、粗纤维、中性洗涤纤维和酸性洗涤纤维含量大于木薯,而同时椰子粕和棕榈粕总磷含量也高于木薯,但钙含量低于木薯。椰子粕和棕榈粕磷表观消化率较木薯日粮显著提高了228.57%和183.57%(P<0.05),而棕榈粕组钙表观消化率较椰子粕组显著提高了107.07%(P<0.05)。棕榈粕组钙摄入量较椰子粕和木薯组分别显著提高了144.17%和71.09%(P<0.05),棕榈粕组粪排泄量最多(P<0.05),而椰子粕和棕榈粕组粪磷占比最高(P<0.05),棕榈粕组每天粪磷排泄量较木薯组显著提高206.25%(P<0.05)。结论:椰子粕和棕榈粕总磷消化率显著高于木薯,但标准磷表观消化率无显著差异。因此,在低磷原料中用标准磷表示可消化磷较总磷更准确。     

内蒙古牧区察哈尔羔羊饲粮钙磷适宜水平研究

本试验采用4个不同钙磷水平的饲粮饲喂断奶后察哈尔羔羊,研究钙磷对断奶羔羊生长、钙磷营养消化代谢和排放量、骨骼的影响。选取70日龄健康、体重(16.27±3.33) kg断奶察哈尔羔羊120只(公母各半),随机分成4个组,每组30个重复,每个重复1只羊,分别饲喂4种饲粮,其钙磷含量分别为:Ⅰ组,0.49%、0.28%;Ⅱ组,0.55%、0.32%;Ⅲ组,0.64%、0.47%;Ⅳ组,0.87%、0.70%。饲养试验期65 d,其后,每组选6只羔羊(公母各半),全收粪法进行消化代谢试验。试验结果:1)饲粮钙磷水平对断奶羔羊平均日增重、体尺、干物质采食量和饲粮转化率影响皆不显著(P>0.05);2)血清钙含量Ⅳ组显著高于其他3组,血清碱性磷酸酶Ⅰ组显著高于其他3组(P<0.05);3)Ⅰ组钙表观消化率显著高于其他3组(P<0.05),随饲粮钙磷水平升高羔羊钙磷排放量增加(P<0.05);4)Ⅳ组胫骨灰分含量显著高于Ⅰ组(P<0.05),Ⅰ组跖骨灰分含量显著低于Ⅲ、Ⅳ组(P<0.05),胫骨磷含量Ⅳ组显著高于其他3组(P<0.05);5)冬春季节改变羔羊饲喂模式增加了内蒙古地区草原生态系统中钙磷的输入。综上所述,饲粮钙磷水平升高降低了断奶羔羊的钙表观消化率,显著增加了钙磷的排放量,提高了羔羊骨骼钙磷沉积。在本试验条件下,饲粮钙磷含量分别为0.49%、0.28%,内蒙古地区冬春季断奶羔羊即可获得较好的生长性能。     

Effects of supplementing low‐quality roughages with tree foliages on digestibility,nitrogen utilization and rumen characteristics in sheep: a meta‐analysis

Thirty‐six published studies containing 219 treatment means and 1069 sheep were included in the dataset for meta‐analysis to elucidate responses of foliage supplementation on digestibility, nitrogen balance and rumen parameters. Major predictive variables were percentages of foliages in diets (FL), crude protein (CP) in foliages (FCP), NDF in foliages (FNDF), NDF in basal forages (BNDF), CP in basal forages (BCP), CP in total diets (DCP) and foliage CP intake (FCPI). Organic matter digestibility increased linearly (p = 0.10) with increasing FL, but responded quadratically to DCP (p = 0.021) and BCP (p < 0.001), with maximal OM digestibility occurred at 14.6% of CP in diets (R² = 0.12). The digestibility of CP was affected by FL (p = 0.01), FCPI (p < 0.026), FCP (p < 0.001), FNDF (p < 0.001) and DCP (p < 0.032) positively and quadratically, and maximal response was at 14.1% DCP (p < 0.001), 51% FL (p < 0.001), 29% FCP (p < 0.001) and FCPI of 122 g/day (p < 0.001). The digestibility of NDF increased quadratically (p = 0.09) with increasing FL, peaking at 16% foliage levels, decreased quadratically (p = 0.001) with increasing FNDF and decreased linearly (p = 0.048) with increasing FCPI. Digestible OM and CP intakes were the highest at 37.2% and 42.1% FL, respectively. Fecal N excretion increased linearly with increasing FL (p < 0.001) and DCP (p < 0.001, R² = 0.66). However, FCPI (p = 0.082), FCP (p = 0.003) and BCP (p < 0.001) affected fecal N excretion positively and quadratically. Urinary N excretion increased linearly (p < 0.001) with increasing FL (R² = 0.45), FCPI (R² = 0.79), FCP (R² = 0.51), BCP (R² = 0.72) and DCP (R² = 0.77). Rumen NH₃ concentration was affected positively and quadratically (p = 0.023) by FL with a peak rumen NH₃ level of 160 mg/l at 17.3% FL. However, rumen NH₃ concentration (mg/l) increased linearly with increasing FCP (p = 0.001), FCPI (p = 0.01) and DCP (p < 0.001). In conclusion, catalytic foliage supplementation at low levels, preferably, at 16% may enhance nutrient utilization, while foliage levels up to 42% may result greater performance of sheep fed on low‐quality roughages.     

Dietary N,N‐dimethylglycine supplementation improves nutrient digestibility and attenuates pulmonary hypertension syndrome in broilers

N,N‐dimethylglycine (DMG) is an intermediary metabolite in cellular choline and betaine metabolism. The present trial aimed to evaluate the effect of dietary DMG on nutrient digestibility and development of pulmonary hypertension syndrome in broilers. A total of 64 14‐day‐old broiler hens (Ross‐308) were raised until age 40 days under cold environmental temperature conditions (15 °C) and were fed a high energy feed in order to incite pulmonary hypertension. Birds were randomly assigned to two groups of which each group had eight replicate pens of four birds each. Test diets contained 0 or 167 mg Na‐DMG (Taminizer^® D; Taminco N.V., Ghent, Belgium)/kg feed. N,N‐dimethylglycine supplementation resulted in a significant improvement in apparent faecal digestibility of crude protein and nitrogen‐free extract. Further, fulminant ascites was numerically lowered by DMG and incidence of pulmonary hypertension decreased significantly from 44.8% in the control group to 14.6% in the DMG group. Finally, fasted plasma level of non‐esterified fatty acids (NEFA) was twofold in the control group in relation to the DMG group. In conclusion, these data demonstrate beneficial effects of DMG on digestibility of non‐fat fractions, on fat metabolism and on progression towards broiler ascites syndrome.     

In vitro microbial protein synthesis,ruminal degradation and post‐ruminal digestibility of crude protein of dairy rations containing Quebracho tannin extract

This study evaluated the effects of Quebracho tannin extract (QTE) on in vitro ruminal fermentation, chemical composition of rumen microbes, ruminal degradation and intestinal digestibility of crude protein (iCPd). Three treatments were tested, the control (basal diet without QTE), the basal diet with 15 g QTE/kg dry matter (DM) and the basal diet with 30 g QTE/kg DM. The basal diet contained (g/kg DM): 339 grass silage, 317 maize silage and 344 concentrate. In vitro gas production kinetic was determined using the Hohenheim gas test (Experiment 1). The Ankom RF technique, a batch system with automatic gas pressure recordings, was used to determine in vitro production of short‐chain fatty acids (SCFA) and ammonia–nitrogen concentration (NH₃‐N), as well as nitrogen and purine bases content in liquid‐associated microbes (LAM) and in a residue of undegraded feed and solid‐associated microbes (Feed+SAM) (Experiment 2). Ruminal degradation and iCPd were determined using the nylon bag technique and the mobile nylon bag technique, respectively (Experiment 3). Gas production (Experiment 1), total SCFA and NH₃‐N (Experiment 2) decreased with increasing QTE levels. Microbial mass and composition of LAM were not affected by QTE, but total mass of Feed+SAM linearly increased, likely due to decreased substrate degradation with increasing QTE levels. The total amount of N in microbial mass and undegraded feed after the in vitro incubation increased with increasing QTE levels, suggesting a potential greater N flow from the rumen to the duodenum. In contrast to in vivo studies with the same QTE, no effects were detected on ruminal effective degradability and iCPd, when using the nylon bag techniques. Based on the in vitro procedures, QTE increased the supply of N post‐rumen; however, some evidence of a decreased fibre degradation were also observed. Therefore, the benefit of adding QTE to diets of cattle is still questionable.     

Changes in diarrhea,nutrients apparent digestibility,digestive enzyme activities of weaned piglets in response to chitosan‐zinc chelate

A total of 120 weanling barrows weighing 6.11 ± 0.20 kg were randomly allotted to four treatments with three replications (i.e. pen) of ten piglets per replicate. Pigs were received corn‐soybean basal diet (control) or the same basal diet supplemented with the following sources of zinc: (i) 100 mg/kg of Zn as ZnSO₄; (ii) 100 mg/kg of Zn as chitosan‐Zn chelate (CS‐Zn); and (iii) 100 mg/kg of Zn as ZnSO₄ mixed with chitosan (CS + ZnSO₄). The results showed that CS‐Zn could highly improve average daily gain and average daily feed intake than those of ZnSO₄ or CS+ ZnSO₄ (P < 0.05). The pigs fed dietary CS‐Zn had lower diarrhea incidence and higher apparent digestibility of crude protein than those of the pigs fed dietary ZnSO₄ (P < 0.05). The protease activities in duodenal content of the pigs receiving CS‐Zn diets was higher than that of the pigs fed dietary ZnSO₄ or CS + ZnSO₄ (P < 0.05). The amylase activity in duodenal content of the pigs fed dietary CS‐Zn was higher than that of the pigs receiving ZnSO₄ diets or basal diets (P < 0.05). These results indicated that dietary CS‐Zn showed different bioactivities from ZnSO₄ or CS + ZnSO₄ in reducing the incidence of diarrhea, improving activities of digestive enzymes and growth performance of weaned pigs.     

ORIGINAL ARTICLE: Impact of feeding level on digestibility of a haylage‐only diet in Icelandic horses

Eight mature Icelandic geldings were used in an experiment arranged as a change‐over design to evaluate the effect of feeding level on the digestibility of a high‐energy haylage‐only diet. The horses were fed a low feeding level 10.7 g dry matter (DM)/kg body weight (BW) (maintenance) and a high feeding level 18.1 g DM/kg BW (1.5 × maintenance) during two 23 days experimental periods. Total collection of faeces was performed for 6 days at the end of each period to determine the coefficient of total tract apparent digestibility (CTTAD). The CTTAD for DM, organic matter, neutral detergent fibre (NDF), acid detergent fibre and energy was higher in horses fed at the low level of feed intake, while feeding level did not affect the CTTAD of crude protein. The largest difference in CTTAD between feeding levels was found for NDF. The content (/kg DM) of digestible energy in the haylage was 11.3 MJ at the low level of feed intake and 10.6 MJ at the high level of feed intake. It can be concluded that feeding level has a large impact on the digestibility and energy value of early cut haylage in Icelandic horses.     

Effects of calcium soap of rice bran oil fatty acids supplementation alone and with DL‐α‐tocopherol acetate in lamb diets on performance,digestibility, ruminal parameters and meat quality

Thirty‐six Malpura lambs (28 day old and 6.7 ± 0.25 kg BW) were distributed equally in three groups having six males and six female. They were ad libitum fed individually three different experimental diets containing calcium soap of fatty acids (CA‐FA) at 0 (T₁) and 40 (T₂ and T₃) g/kg concentrate up to six months of age. Animals in T₃ were supplemented additionally with 40 mg DL‐α‐tocopherol acetate/kg of concentrate. The roughage moiety included ad libitum dry Prosopis cineraria and fresh Azadirachata indica leaves. All the lambs were allowed to suckle from their dam up to weaning (90 day of age). Supplementation of Ca‐FA improved weight gain and feed conversion ratio during both pre‐ (28–90 days) and post‐weaning (91–180 days) phases; however, no effect of DL‐α‐tocopherol was observed. Metabolic parameters during post‐weaning phase revealed non‐significant effect on digestibility but improved nitrogen balance in the test groups. The effect on biochemical attributes did not show any significant alteration in ruminal parameters, blood biochemicals and urinary purine derivatives. Carcass traits revealed higher (p < 0.05) dressing yield and loin eye area with Ca‐FA supplementation. The value of thiobarbituric reactive substances for nuggets prepared from frozen carcasses revealed significant (p < 0.05) reduction in T₃ compared to the other dietary groups. Fatty acid profile of adipose tissue revealed higher (p < 0.001) 9‐octadecanoic, 9‐12‐octadecadienoic, polyunsaturated fatty acids (PUFA), higher ratio of PUFA/saturated fatty acids (SFA), ω‐6/ω‐3 and lower SFA in Ca‐FA‐supplemented groups. It is concluded that supplementation of 40 g/kg calcium soap prepared from industrial grade rice bran oil in lamb ration provided additional energy intake, improved N utilization, gain and feed conversion ratio besides improving dressing yield and meat quality with CLA enriched fatty acid profile. DL‐α‐tocopherol acetate when supplemented at 40 mg/kg feed reduced lipid oxidation of meat products thus improving its keeping quality.