Transfer of blood urea nitrogen to cecal microbial nitrogen is increased by fructo‐oligosaccharide feeding in guinea pigs

The present study was conducted to determine the mechanism by which nitrogen (N) availability is improved by fructo‐oligosaccharide (FOS) in guinea pigs. Adult male guinea pigs were fed a commercial pellet diet (50 g/day) with either 5% glucose or 5% FOS for 7 days in individual metabolism cages. After 7 days of feeding the diet, ¹⁵N‐urea was administered intravenously 1 h before slaughter under anesthesia. The amount and concentration of total, protein, bacterial, ammonia and urea N and the ¹⁵N atom % excess were measured in blood, liver, gut contents and urine. The ¹⁵N atom % excess of total and protein N, and the amount of total, protein and bacteria N and ¹⁵N in the cecum were significantly increased by the consumption of FOS. Furthermore, the concentration and amount of short‐chain fatty acids were significantly increased by the consumption of FOS. In contrast, the amount of urinary ¹⁵N was significantly decreased by the consumption of FOS. These results suggest that consumption of FOS increases transfer of blood urea N into the large intestine for bacterial N synthesis, which is subsequently re‐absorbed by cecotrophy, and contributes to the increase of N utilization in guinea pigs.     

Effect of fructo‐oligosaccharide on nitrogen utilization in guinea pigs

The present study was conducted to determine the effects of fructo‐oligosaccharide (FOS) on the nitrogen (N) utilization and digestibilities of dietary nutrients through cecotrophy in guinea pigs. Adult male guinea pigs that were housed or not housed in wooden frames to prevent cecotrophy were fed a commercial pellet diet (50 g/day) with 3% and 5% glucose or FOS for 8 days in individual metabolism cages. In the guinea pigs allowed cecotrophy, addition of FOS to the diet had no significant effects on body weight gain or apparent digestibility of N, but showed significantly lower value for the urinary N excretion and acid‐detergent fiber digestibility (P < 0.05 and P < 0.01, respectively) and significantly higher value for N retention and the N retention rate (P < 0.05). In the guinea pigs prevented from cecotrophy, FOS had no effect on N retention, but showed tendencies toward a higher value for fecal N excretion and a lower value for urinary N excretion. These results suggest that FOS stimulates cecal microbial proliferation, thereby improving N utilization in guinea pigs.     

Effect of D‐mannitol on nitrogen retention,fiber digestibility and digesta transit time in adult rabbits

The aim of the current study was to elucidate the effect of gastrointestinal retention time of digesta on fiber digestibility in adult rabbits fed indigestible, but fermentable, sugar D‐mannitol. Six adult rabbits were fed alternately a commercial diet containing 5% glucose and a diet containing D‐mannitol. Total feces and urine were collected during the experimental period. Nitrogen (N) balance, digestibility of nutrients, and gastrointestinal mean retention time (MRT) were measured. The results indicated that urinary excretion was significantly lowered, whereas N retention and N accumulation rates were significantly increased in the D‐mannitol group compared with the glucose group (P < 0.05). However, fecal N excretion was unaffected. Absorption of crude ash (CA) and acid detergent fiber (ADF) digestibility were significantly higher in the D‐mannitol group compared with the glucose group (P < 0.05). The addition of D‐mannitol to the diet did not affect the MRT of liquid digesta, but increased the MRT of solid digesta compared with the glucose group (P < 0.05). These results suggest that the addition of D‐mannitol to the diet stimulates cecal bacterial growth, thereby increasing N utilization and digesta retention time.     

Effect of fructo‐oligosaccharides on nutrient digestibility and digesta retention time in adult guinea pigs

A previous study suggested that addition of fructo‐oligosaccharides (FOS) to the diet improved nitrogen (N) utilization and decreased acid detergent fiber (ADF) digestibility in guinea pigs. The present study was conducted to clarify the relationship between ADF digestibility and gastrointestinal mean retention time (MRT) in guinea pigs under FOS supplementation. Adult male guinea pigs were fed a commercial diet (50 g/day) with either 5% glucose (glucose group) or 5% FOS (FOS group) for 12 days in individual metabolism cages. Unlike the glucose group, N utilization improved, but ADF digestibility significantly (P < 0.05) decreased in the FOS group. MRT of solid digesta also significantly (P < 0.05) decreased in the FOS group compared with that in the glucose group. We concluded that reduction of MRT of solid digesta containing FOS decreased ADF digestibility in guinea pigs.     

Effects of adding urea on fermentation quality of pruned persimmon branch silage and its digestibility,preference, nitrogen balance and rumen fermentation in beef cattle

Four cattle were used in a 4 × 4 Latin square design experiment to study digestibility, ruminal fermentation, nitrogen retention and preference of ensiling pruned persimmon branch (PPB) chips treated with urea. After 60 days of ensiling, urea‐treated PPB showed higher (P < 0.05) pH, acetic acid and ammonia‐N levels than no‐urea PPB. Both urea‐treated PPB and rice straw diets showed higher (P < 0.05) apparent digestibility and digestible nutrient content in cattle than no‐urea PPB diet. Neither mold nor yeast was detected in any urea‐treated PPB. Urinary and fecal excretion as well as nitrogen retention in cattle fed urea‐treated PPB were higher (P < 0.05) than in those fed no‐urea PPB and rice straw. With the exception that ruminal ammonia‐N levels in cattle fed urea‐treated PPB were higher (P < 0.05) than in those given no‐urea PPB and rice straw, ruminal pH, volatile fatty acid concentrations, and the acetic : propionic acid ratio of rumen content were unaffected by diets. The rank order of preference was rice straw > low‐urea > no‐urea > high‐urea. The results suggested that urea treatment of PPB inhibited growth of mold and yeast during silage storage, enhanced its digestibility and had nutritive value almost equivalent to that of rice straw.     

Utilization of dietary urea nitrogen is stimulated by D‐mannitol feeding in rabbits

The effect of D‐mannitol as an indigestible sugar on apparent digestibility of nutrients, nitrogen (N) utilization and growth performance, have been investigated in growing rabbits fed a urea‐containing diet. In experiment 1, 40‐day‐old male rabbits were fed a commercial diet with urea 10 g/kg with added glucose or D‐mannitol 60 g/kg each. Thereafter, in experiment 2 the rabbits aged 55 days were fed a commercial diet with or without urea 10 g/kg. Feed restriction at 55 g/kg^0.75/day was carried out in both experiments. Addition of D‐mannitol to the urea‐containing diet decreased urinary N excretion, which consequently increased N retention and ratios of retained N to consumed N or apparently absorbed N. Addition of urea alone to the diet increased daily N intake and urinary N excretion but did not affect N retention. Weight gain and feed efficiency were improved by D‐mannitol feeding, whereas feeding with urea alone did not affect these parameters. Utilization of dietary urea was enhanced in growing rabbits fed the urea‐containing diet with D‐mannitol, resulting in improvement of N retention and growth performance.     

Effect of colostomy on the occurrence of dietary [15N]urea in intestinal contents,blood, urine and tissues in chickens fed a low protein diet plus urea

1. The occurrence of ¹⁵N was examined in excreta for 10 h, and in intestinal contents, blood and tissues at 10 h after [¹⁵N]urea was fed to conventional and colostomised cockerels.

2. Total‐¹⁵N excretion and ¹⁵N‐balance in control chickens were 18.88 and 44.79 mg/kg body weight/10 h), respectively. The former was increased and the latter was decreased by colostomy by 10.75 mg (P<0.01).

3. Amounts of [¹⁵N]urea, [¹⁵N]ammonia and [¹⁵N]uric acid excreted by control birds were 13.78, 3.90 and 0.18 mg/kg body weight/10 h or 0.73, 0.21 and 0.01 of the total‐¹⁵N excreted respectively.

4. The [¹⁵N]urea, [¹⁵N]uric acid and total‐¹⁵N excreted were all increased after colostomy but [¹⁵N]ammonia was decreased (uric acid P<0.05, others P<0.01). The increase in total‐¹⁵N was mostly accounted for by [¹⁵N]urea.

5. Colostomy resulted in significantly less total‐¹⁵N in the contents of the whole intestine (P<0.01), less total‐¹⁵N, [¹⁵N]ammonia and [¹⁵N]urea in the contents of the co!o‐rectum (P<0.01) and less total‐¹⁵N and [¹⁵N]urea in the contents of the upper intestine (P< 0.05); it did not affect any in caecal contents.

6. [¹⁵N]Urea in blood, liver and kidney (blood P<0.01, others P< 0.05), and [¹⁵N]glutamine amide (P< 0.05) and [¹⁵N]uric acid (P< 0.01) in blood were significantly decreased after colostomy.

7. The results support the hypothesis that most of the dietary urea is utilised as the result of a back‐flow of ureteral urea into the caeca where it is rapidly converted into ammonia which is then metabolised to other compounds.     

Effect of dietary inclusion of sorghum milling waste on growth response,nutrient utilisation,gut characteristics and cecal microflora of weaner rabbits

Growth response, nutrient digestibility and cecal microflora of 80 male, mixed breed weaner rabbits fed with varying dietary inclusions of sorghum milling waste (SMW) was investigated. Four experimental diets were formulated such that SMW was included at 0 (control), 100, 200 and 300 g/kg, respectively. Each dietary treatment was performed on 20 rabbits. Feed intake increased (P < 0.05) while final live weight and feed conversion ratio of rabbits decreased (P < 0.05) following increased dietary inclusion of SMW. Rabbits fed with 100 and 200 g/kg SMW had similar feed conversion ratios, weight gain, crude fiber, dry matter and crude protein digestibility values. Rabbits fed with 300 g/kg SMW recorded the lowest (P < 0.05) hot carcass weight, dressing percentage and rack weight. Similar dressing percentage and rack weight were recorded for rabbits fed with control diet, 100 and 200 g/kg SMW. The weight of cecal content increased (P < 0.05) with increased dietary inclusion levels of SMW. Rabbits fed with 300 g/kg SMW recorded the lowest (P < 0.05) coliform and lactobaccillus counts. Dietary inclusion of up to 200 g/kg SMW supported improved growth response and carcass yield without imposing any detrimental effect on cecal microflora.     

The comparative study digestion and metabolism of nitrogen and purine derivatives in male, Thai, Swamp buffalo and Thai, Brahman cattle

Studies on in vivo digestion, rates of passages, metabolism of nitrogen, urinary purine derivative excretion and blood metabolites were carried out in Thai Brahman cattle and Thai swamp buffaloes (16 months old). The animals were fed mixed diets based on pineapple (Ananas comusus) waste silage containing urea‐N (NPN) and true protein from a concentrate (TP). The Brahman cattle (310 ± 15 kg) were heavier than the swamp buffaloes (195 ± 9.4 kg) and had higher dry matter (DM), organic matter (OM) and neutral detergent fiber (NDF) intakes when compared on the basis of their metabolic body weight (BW^0.75), but these intakes did not differ significantly when the diets of each animal species were compared. The total tract, apparent digestibilities of dry matter (DM) and organic matter (OM) were not significantly different between the animal species when comparing the two types of diets. The NDF digestibility was significantly (P < 0.01) decreased in both animal species when fed the TP diet, but was significantly (P < 0.01) greater in cattle than in swamp buffaloes. The passage rate digesta k₁ (P < 0.01) and the passage rate digesta k₂ (through the caecum and proximal colon) (P < 0.03) were significantly slower, and the total mean retention time (TMRT) (P < 0.01) was significantly longer in swamp buffaloes when compared to Brahman cattle, but the transit time (TT) showed no difference (P = 0.07) between the animal species or the diets. The N intakes were not different in both animal species and diets, but urine‐N was greater (P < 0.05) in Brahman cattle than that in swamp buffaloes. Urine N and digestibility of N were significantly (P < 0.04) higher in animals fed the NPN diet than those fed the TP diet. Urinary purine derivatives (PD) and the creatinine (Cr) excretion of swamp buffaloes were significantly (P < 0.01) lower than those in Brahman cattle. Plasma urea‐N (BUN) concentration was significantly (P < 0.01) higher in swamp buffaloes than that in Brahman cattle, but plasma glucose and insulin concentrations were significantly (P < 0.01) higher in Brahman cattle than in swamp buffaloes. The concentrations of non‐esterified fatty acids (NEFA) were not significantly (P > 0.05) different in animals fed different diets. The present study demonstrated that Brahman cattle were better in fiber digestibility than swamp buffaloes at utilizing pineapple waste silage with both N sources.     

Adaptive changes in microbial synthesis and nitrogen balance with progressing dietary feeding periods in sheep fed diets differing in their ruminal degradation synchronicity between nitrogen and organic matter

Two diets differing in their degrees of ruminal degradation synchronicity between nitrogen (N) and organic matter (OM) were fed to six adult rams at a maintenance level for three months in a two‐way layout design combining a randomized block design. Adaptive changes in microbial N (MBN) supply and N balance were investigated for both diets. The in situ rumen degradation parameters of OM and N were determined for four feeds and subsequently were used to formulate the two diets to have different ruminal degradation synchronicity and to be identical with metabolizable energy (ME), metabolizable protein (MP) and ruminally degradable N concentrations. The animals were divided into two groups and fed asynchronous (ASYNC) or synchronous (SYNC) diet, respectively. On days 30, 60 and 90 of each feeding period, a five‐day metabolism trial was carried out. Animals consumed their diets thoroughly and did not show marked body weight change during the observation. The apparent digestibility of OM and N did not differ significantly between the diets throughout the periods. The MBN supply was significantly greater for ASYNC than that for SYNC (P < 0.01) and was greater on days 60 and 90 than that on day 30 (P < 0.05). Neither diets nor periods had a significant effect on the efficiency of MBN synthesis. There was a significant period effect on N retention (P < 0.05) together with tendency of diet × period interactions (P = 0.1). There was no significant dietary effect. An improvement in N retention with advancing feeding period was observed for both diets. The plasma urea concentration decreased with feeding period (P < 0.01) and there was a concomitant decrease in urinary N excretion. Plasma glucose concentration tended to increase (P = 0.07). The results suggest that lengthening feeding duration from 30 days might have caused ameliorative changes in the utilization of ME and MP, and may have improved microbe synthesis irrespective of the degradation synchronicity.     

Effects of different fermented soy protein and apparent ileal digestible lysine levels on weaning pigs fed fermented soy protein‐amended diets

Two experiments were conducted to evaluate the effect of different fermented soybean proteins and the apparent ileal digestible lysine levels on weaning pigs fed fermented soy protein (FSP)‐amended diets. In Exp. 1, 70 crossed piglets (6.25 ± 0.40 kg) were used in a 5‐week trial to evaluate two different FSP. In Exp. 2, 20 weaning barrows (6.15 ± 0.45 kg) were used in a metabolism trial to determine the effects of the apparent ileal digestible (1.2, 1.3, 1.4 and 1.5%) lysine levels in weaning pigs fed FSP (5%) diet. In Exp. 1, pigs fed the diet containing Lactobacillus spp. FSP showed higher nitrogen (N) digestibility (P < 0.05), lower blood urea nitrogen and serum creatinine levels (P < 0.05) than those fed the Aspergillus oryzae FSP diet. In Exp. 2, increasing dietary lysine levels increased the average daily gain, apparent dry matter, N digestibility, N retention and essential amino acids in the current study (P < 0.05), with the 1.5% showing the highest value. In conclusion, pigs fed Lactobacillus spp. FSP had a higher N digestibility than those fed A. oryzae FSP. The optimal apparent ileal digestibility lysine level in fermented soy protein diets (3550 kcal/kg metabolizable energy) for maximizing growth performance and N utilization in the first 7 days (6.25 kg) was 1.5%.     

Effect of dietary protein on intake,nutrients utilization,nitrogen balance,blood metabolites,growth and puberty in growing Bhadawari buffalo (Bubalus bubalis) heifers

Fifteen Bhadawari buffalo heifers of 207?±?9.78 kg mean body weight were randomly distributed into three dietary groups to evaluate the effect of protein level on nutrient utilization, nitrogen (N) balance, growth rate, blood metabolites, and puberty. All animals were offered wheat straw-berseem diets supplemented with concentrate mixtures of similar energy (2.7 Mcal/kg) and different protein levels (14.3–22 %). Animals of standard-protein group (SPG) were offered protein and energy as per requirement, while animals of low-protein group (LPG) and high-protein group (HPG) were fed 20 % less and 20 % more protein, respectively, than SPG. Feed dry matter (DM) and metabolizable energy (ME) intake (% body wt. and g/kg w^0.75) were similar for all three diets; however, the crude protein (CP) and digestible crude protein (DCP) intake on percent body weight and per kilogram metabolic weight was higher (P?<?0.05) in HPG than in SPG or LPG. Digestibility of CP, cellulose, and hemicellulose was higher (P?<?0.05) in HPG versus LPG. Fecal N excretion was similar, while urinary N excretion was highest (P?<?0.05) in HPG (74.83 g/day) compared with SPG (50.03 g/day) and LPG (47.88 g/day), which resulted in lower N retention in HPG than in the other dietary groups. Level of dietary N had no effect on blood metabolites viz. glucose, urea, and N. Digestible energy (DE) and ME contents of diets were identical, while DCP contents were higher (P?<?0.05) in HPG than in LPG. Feed and nutrient (CP and ME) conversion efficiency to produce a unit kilogram weight gain was identical among the dietary groups. Dietary protein level had no effect on the heifer’s weight and age at puberty. The mean growth rate of heifers at 240 days was higher (P?>?0.05) in SPG (330.8 g/day) than in LPG (296.7 g/day), while the animals gained more weight in January to March months and the lowest weight in May to July months. Protein level had no effect on conception rate of heifers. Results revealed that 20 % higher or less protein than the ICAR requirement had no significant (P?>?0.05) on feed intake, nutrient conversion efficiency for weight gain, heifer growth, and puberty; however, 20 % more protein increased urinary N loss.

     

低蛋白质饲粮中添加尿素对肉兔消化代谢的影响

本试验旨在研究低蛋白质饲粮中添加尿素对肉兔消化代谢的影响。采用单因子随机区组试验设计,选择 ９０只 ５０日龄体重相近的健康新西兰兔,随机分为 ３组,１个对照组和 ２个试验组,每组 １５个重复,每个重复 ２只。对照组饲喂粗蛋白质含量为 １１．１１％的基础饲粮,２个试验组分别饲喂在基础饲粮中以糊化淀粉缓释尿素的方式添加 １％、２％和 ３％尿素的试验饲粮。预试期为 １０ｄ,正试期为 ３０ｄ。正试期的第 １３～１８天收集试验兔排出的全部粪便和尿液。结果表明：与对照组相比,１％尿素组试验兔的有机物表观消化率、总能表观消化率及利用率、沉积氮、氮利用率和消化氮利用率显著或极显著升高（Ｐ＜０．０５或 Ｐ＜０．０１）,而 ２％尿素组试验兔的消化能、代谢能、沉积氮、氮利用率和消化氮利用率显著或极显著降低（Ｐ＜０．０５或 Ｐ＜０．０１）。对照组试验兔盲肠内容物脲酶活性和微生物蛋白浓度显著或极显著低于其余 ２组（Ｐ＜０．０５或 Ｐ＜０．０１）,而 ２％尿素组试验兔盲肠内容物氨氮和尿素氮浓度显著或极显著高于其余 ２组（Ｐ＜０．０５或 Ｐ＜０．０１）。由此得出,低蛋白质饲粮中添加 １％尿素可改善肉兔有机物、总能和氮的利用效率,提高盲肠内容物脲酶活性和微生物蛋白浓度;添加 ２％尿素则会降低肉兔氮的利用效率,提高盲肠内容物脲酶活性及微生物蛋白、氨氮和尿素氮浓度。     

The rate and pattern of urea infusion into the rumen of wethers alters nitrogen balance and plasma ammonia

Changes in N balance, urinary excretion of purine derivative (PD), urea, creatinine and ammonia and plasma ammonia, glucose, urea, insulin and IGF‐1 were examined in four wethers (37 ± 2.6 kg BW). The animals were fitted with permanent ruminal catheters, fed lucerne hay (9.4 MJ/day; 23 g N/day; 7 g soluble N/day, 6 equal meals/day) and treated with contrasting rates of urea infusion into the rumen: first, a continuous infusion (CT), at 3.2 mg urea‐N/min for 10 days and then a discontinuous infusion (DT) at 156 mg urea‐N/min for 4 min; in 6 daily doses with the meals for 7 days. N balance was calculated from pooled samples of faeces and urine. Jugular blood samples were collected before and 1.5 h after the morning meal (M1) on days CT10, DT2, DT4 and DT6. N retention decreased during DT (p = 0.01) due to a significant increase of N excretion in urine (4 g/day; p = 0.009) and faeces (1 g/day; p = 0.02). Dry matter (p < 0.001) and N digestibility in vivo (p = 0.01) decreased significantly during DT. Urinary urea and PD excretion were not altered by treatment. Significant linear (p = 0.004) and quadratic (p = 0.001) effects were observed for plasma ammonia in M1 (from 170 CT10 to 235 μm DT2 and returned to 120 μm DT6). No changes were observed in plasma glucose, urea, insulin and IGF‐1. Results indicate that changes from CT to DT reduced N retention in sheep due to enhanced urinary N excretion, but it was not associated with changes in urinary urea or PD excretion; or plasma concentrations of insulin and IGF‐1. As the dry matter (DM) an N digestibility could account a 0.23 of the decrease in N retention; the largest fraction of the reduction in N retention remained unexplained by the results.     

Effects of supplement feeding order on lactation, diurnal variation of ruminal ammonia and urea in the blood and milk of dairy cows

The present study examined the effects of feeding order of grain and protein supplements on ruminal nitrogen (N) loss through the diurnal variation of ruminal ammonia N and urea N in the blood and milk of dairy cows. Three ruminally fistulated cows were used in a 3 × 3 Latin square arrangement of treatments; that is, grain supplement fed at the first feed and then the protein supplement at the second (GS‐1st), protein supplement fed first and then the grain supplement (PS‐1st), and the grain and protein supplements mixed and divided into equal portions fed at each supplement feeding time (GP‐mix). No differences in the lactation parameters were observed among the treatments. In GS‐1st treatment, the increase in the concentration of ruminal ammonia N was inhibited after feeding, and the concentration was lower (P < 0.05) than with the other treatments 1–2 h after basal feeding. The concentrations of urea N in the blood and milk with the GS‐1st treatment were the lowest of all treatments throughout the sampling times, and were lower (P < 0.05) than with the GP‐mix treatment except for blood levels 1 h after basal feeding. The results suggest that grain feeding before protein feeding can reduce ruminal N loss.     

Effect of feeding garlic leaf on microbial nitrogen supply,kinetics of plasma phenylalanine,tyrosine and protein synthesis in sheep

The objective of the present study was to assess the feeding effects of garlic leaf on microbial N supply (MNS), turnover rates of plasma phenylalanine (PheTR) and tyrosine (TyrTR) and whole body protein synthesis (WBPS) in sheep. The sheep were fed either mixed hay (Hay‐diet, as control) or hay plus garlic leaf diet (GL‐diet, at a ratio of 9:1) in a crossover design each for a 21 day period. The isotope dilution method using [²H₅]Phe and [²H₂]Tyr was performed on the 21st day of each dietary treatment. Nitrogen intake remained similar between the diets and N absorption and N digestibility were higher (P < 0.05) in the GL‐diet than Hay‐diet. Total purine derivatives excretion and MNS were greater (P < 0.05) in the GL‐diet than the Hay‐diet. Plasma PheTR tended to be higher (P = 0.06) during GL feeding and TyrTR did not differ between the diets. Further, WBPS tended to be greater (P = 0.05) for the GL‐diet compared with the Hay‐diet. Hence, the present results suggest that garlic leaf may have positive effects on N metabolism by influencing MNS in sheep and could be used as a potential ruminant feed in the future.     

Evaluation of standardized ileal digestible lysine requirement for 8–20 kg pigs fed low crude protein diets

Two experiments were conducted to determine the standardized ileal digestible lysine (SID Lys) requirement for weaned pigs fed with low crude protein (CP) diet. In Experiment 1, 144 pigs were fed a normal CP (20%) diet with 12.3 g/kg SID Lys and five low CP (18.5%) diets providing SID Lys levels of 9.8, 11.1, 12.3, 13.5, and 14.8 g/kg, respectively, for 28 days. Reducing dietary CP from 20% to 18.5% enhanced (p < 0.05) the growth performance. The average daily gain (ADG) and gain to feed ratio (G:F) increased (linear and quadratic; p < 0.05), serum urea nitrogen (SUN) decreased (linear and quadratic; p < 0.05) as SID Lys increased. The SID Lys levels required to maximize ADG and optimize G:F were 12.8 and 13.1 g/kg using a curvilinear plateau model, and to minimize SUN was 13.4 g/kg using a two‐slope broken‐line model, which averaged 13.1 g/kg SID Lys. In Experiment 2, 18 pigs were used in a 12‐day N balance trial and received the same diets of Experiment 1. Total N excretion was decreased when dietary CP reduced and further decreased when SID Lys increased. Collectively, 1.5% dietary CP reduction improved the growth performance and decreased the N excretion; the optimal SID Lys requirement was at 13.1 g/kg of 8–20 kg pigs fed with 18.5% CP diet.     

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.     

Effect of fat supplementation during transition period on plasma leptin and non‐esterified fatty acid concentrations in Holstein cows

The objective of this experiment was to investigate the effect of fat supplementation during the transition period on pre and postpartum body weight (BW), body condition score (BCS), non‐esterified fatty acids (NEFA), glucose and leptin concentrations in Holstein cows. Holstein cows (n = 15) received a low fat diet (LF; 1.61 Mcal net energy for lactation (NEL)/kg of dry matter [DM]), moderate fat diet (MF; 1.68 Mcal NEL/kg DM) or a high fat diet (HF; 1.74 Mcal NEL/kg DM) for 4 weeks prior to calving. All cows were fed similar lactation diets ad libitum (1.74 Mcal NEL/kg DM) for 30 days after calving. Increasing diet energy density during transition period had no effect on prepartum DMI, BCS, BW, glucose and NEFA concentrations (P > 0.05); but leptin concentrations and energy balance (EB) were affected by treatments (P < 0.05). Animals fed HF had less plasma leptin prepartum. After parturition, BW, milk production, milk fat, protein, urea nitrogen and plasma glucose concentrations were affected by prepartum diets (P < 0.05). Fat supplementation prepartum did not affect postpartum NEFA. In conclusion, prepartum fat supplementation decreased leptin concentration prepartum.     

Medium‐chain triglyceride as an alternative of in‐feed colistin sulfate to improve growth performance and intestinal microbial environment in newly weaned pigs

Five hundred and twenty‐eight newly weaned pigs were given four treatments, with eight replicates per treatment. Sixteen to 18 pigs were assigned per replicate and were fed diets supplemented with 0 or 3% medium‐chain triglyceride (MCT) and 0 or 40 ppm colistin sulfate (CS) in a 2 × 2 factorial arrangement for 2 weeks. The results showed that dietary supplementation with MCT improved the gain‐to‐feed ratio during days 3‐7 and in the overall period (P < 0.05). Dietary supplementation with MCT decreased coliforms counts (C) in colon and rectum content (P < 0.05). Dietary supplementation with CS decreased C and lactic acid bacteria plus C counts (L + C) in cecum (P < 0.05), and C, L + C (P < 0.01) and ratio of L and C (P < 0.05) in colon and rectum contents. The lack of interactions between MCT and CS indicates different modes of action and additive effects between the two supplementations. In conclusion, supplementation with MCT in diet with or without CS could improve the intestinal microbial environment and the feed utilization efficiency of newly weaned pigs.