Nutritional evaluation of transgenic high‐methionine lupins (Lupinus angustifolius L) with broiler chickens

The nutritive value of transgenic lupin seeds (Lupinus angustifolius L) with higher contents of methionine was evaluated with broiler chickens. The crude protein, methionine and cysteine contents in the conventional and transgenic lupins were 322 and 324, 2.0 and 4.5, and 3.6 and 3.7 g kg^?1 dry matter respectively. In the feeding trial, conventional and transgenic lupins with hulls were incorporated into a maize–soyabean meal diet at 250 g kg^?1 level and the diets were fed to female broiler chicks from 6 to 20 days of age. All diets were balanced to contain similar levels of apparent metabolisable energy (AME), lysine and sulphur‐containing amino acids. The levels of free methionine added to the maize–soyabean meal control, conventional lupin and transgenic lupin diets were 2.2, 2.8 and 2.2 g kg^?1 respectively. Weight gain and feed intake were not influenced by dietary treatments, but feed/gain tended to be higher (P = 0.09) in birds fed lupin diets compared with those fed the control diet. Feed/gain of birds fed the conventional lupin diet was higher (1.82 vs 1.74) than for those fed the transgenic lupin diet. These results showed that the supplemental methionine required in poultry diets containing 250 g kg^?1 lupin can be lowered by 0.6 g kg^?1 diet by the use of high‐methionine lupins. The AME values of conventional and transgenic lupins were determined to be 9.42 and 10.18 MJ kg^?1 dry matter respectively. The higher AME value in transgenic lupins may be related to the lower content of soluble non‐starch polysaccharides (45.6 vs 60.7 g kg^?1 air‐dry basis). Data on ileal amino acid digestibility indicate that the amino acids in transgenic lupins are as digestible as those in conventional lupins. © 2002 Society of Chemical Industry     

Nitrogen solubility in three solvents and in situ protein degradability of ruminant feedstuffs

Feedstuffs commonly fed to ruminants were assayed for nitrogen solubility by using McDougall's buffer, 0·02 M sodium hydroxide (NaOH), or 0·15 M sodium chloride (NaCl) as solvents. In addition, in situ dry matter and protein disappearance from the same feedstuffs were determined using the nylon bag technique in ruminally cannulated sheep for varying times of incubation. The mean effective nitrogen disappearance ranged from 235 for maize to 894 g kg⁻¹ of total N for lupins, and dry matter disappearance from 240 for meat and bone meal to 793 g kg⁻¹ for lupins. Protein solubility was lowest (<10% of total N) for oilseed by-products and animal and fish by-products, intermediate (15–30% of total N) for some cereals and highest (35–45% of total N) for wheat varieties and plant protein sources. Furthermore, solubility and degradability data for various feed proteins are presented which demonstrate the variability in solubility and degradability of ruminant feedstuffs due to protein type or processing. © 1997 SCI.     

Ileal digestibility of defatted soybean,lupin and chickpea seed meals in cannulated Iberian pigs: II. Fatty acids and carbohydrates

Five castrated male Iberian pigs (100 ± 2 kg mean live body weight) fitted with T‐shaped ileal cannulas were used to determine ileal digestibility of legume seed meals. The diets were based on defatted soybean (256 g kg^?1), lupin (451 g kg^?1) or chickpea (731 g kg^?1) seed meals and contained similar amounts of digestible energy (14.2–15.1 kJ g^?1) and protein (107 g kg^?1). Only myristic acid (C14:0) ileal apparent digestibility was higher (p < 0.05) in lupin than in chickpea meal. Ileal apparent digestibility of unsaturated fatty acids (FA) (710–920 g kg^?1) was higher (p < 0.05) than that of saturated (480–710 g kg^?1) FA for both seed meals. Ileal digestibility of chickpea starch was 850 g kg^?1. Ileal digestibility of oligosaccharides (sucrose, raffinose, stachyose, verbascose and ciceritol) in lupin (820 g kg^?1) and chickpea (690 g kg^?1) was higher (p < 0.05) than that of defatted soybean (510 g kg^?1). However, total amounts of oligosaccharides digested were higher (p < 0.05) for lupin and chickpea meals (29.6 and 24.6 g kg^?1 feed respectively) than for soybean (15.2 g kg^?1 feed). Among individual non‐starch polysaccharide (NSP) sugars, ileal digestibility values for rhamnose and xylose in lupins were higher (p < 0.05) than those for soybean or chickpea. Ileal digestibility of lupin meal NSP (650 g kg^?1) was higher (p < 0.05) than those of soybean (560 g kg^?1) or chickpea (430 g kg^?1). Up to the terminal ileum, higher (p < 0.05) amounts of lupin total NSP (94.1 g kg^?1) than for soybean (24.3 g kg^?1) or chickpea (27.1 g kg^?1) were digested. Lactate, acetate and isobutyrate concentrations were higher (p < 0.05) in ileal contents of pigs fed lupin and chickpea seed meals compared with soybean‐fed animals. It is concluded that higher lactate and short chain fatty acids concentrations in ileal contents of pigs fed lupin or chickpea seed meals compared with soybean are likely to be the result of higher total amounts of lupin NSP and/or lupin and chickpea oligosaccharides digested up to the terminal ileum. This might have a protective effect on Iberian pig's intestinal physiology. Both lupin and chickpea meals are likely to constitute a valuable alternative to defatted soybean in Iberian pig feeding. Copyright © 2005 Society of Chemical Industry     

Chemical composition and ruminal degradability of lucerne (Medicago sativa) products

A study was conducted to determine the chemical composition and in situ nutrient ruminal degradability of three lucerne products. These were dehydrated pellets, sun‐cured pellets and cubes. Results of the chemical analysis showed that sun‐cured pellets had the highest (P < 0.05) neutral and acid detergent fibre as well as total carbohydrate levels, followed by cubes and dehydrated pellets respectively. Crude protein (CP) content was highest (P < 0.05) for dehydrated pellets (204.3 g kg^?1), intermediate for sun‐cured pellets (160.0 g kg^?1) and lowest for cubes (153.2 g kg^?1). Intermediately degradable CP (buffer‐insoluble CP minus neutral detergent‐insoluble CP) was the main protein fraction in the three products and was higher (P < 0.05) in cubes than in dehydrated and sun‐cured pellets. Estimated net energy of lactation was highest (P < 0.05) for dehydrated pellets (5.9 MJ kg^?1), intermediate for cubes (5.23 MJ kg^?1) and lowest (P < 0.05) for sun‐cured pellets (5.15 MJ kg^?1). Results of the in situ experiment indicated that dehydrated pellets had higher (P < 0.05) ruminal protein degradability than sun‐cured pellets and cubes. The estimated ruminal escape protein values for dehydrated pellets, sun‐cured pellets and cubes were 361, 420 and 498 g kg^?1 CP respectively. It was concluded that differences in chemical composition and ruminal degradability among the three lucerne products were mainly due to differences in stage of maturity. It was also concluded that the dehydration process failed to increase the ruminal escape protein value of dehydrated pellets relative to sun‐cured pellets and cubes. © 2001 Society of Chemical Industry     

Chemical characterisation and ruminal nutrient degradability of hulled and hull-less oats

The objectives of this study were to determine the chemical and ruminal nutrient degradability characteristics of two hulled (Calibre and AC Mustang) and one hull-less (AC Belmont) oat varieties. Ruminal nutrient degradability characteristics of the oat varieties were determined relative to barley using one ruminally fistulated cow. Neutral (NDF) and acid (ADF) detergent fibre levels were higher (P < 0·05) in hulled than hull-less oats. Hulled AC Mustang had higher (P < 0·05) NDF and ADF content than hulled Calibre. Starch content was higher (P < 0·05) in AC Belmont (590 g kg⁻¹) than Calibre (457 g kg⁻¹) and was higher in Calibre than AC Mustang (415 g kg⁻¹). Crude protein was higher (P < 0·05) in hull-less than hulled oat. Both hulled varieties had similar CP content (average 124 g kg⁻¹). Estimated digestible energy value was highest (P < 0·05) for AC Belmont (16·94 MJ kg⁻¹), intermediate for Calibre (14·18 MJ kg⁻¹) and lowest for AC Mustang (13·34 MJ kg⁻¹). Ruminal dry matter and NDF degradability were higher (P < 0·05) in hull-less than barley and was higher in barley than hulled oats. Ruminal starch degradability exceeded 900 g kg⁻¹ for all tested feeds and had the order AC Belmont = barley > Calibre = AC Mustang. It was concluded that oat varieties used in this study varied considerably in their chemical composition and ruminal degradability. When compared with barley, hulled oats had lower while hull-less oats had higher ruminal degradability. © 1998 SCI.     

Analytical composition and rumen degradability of isogenic and transgenic corn varieties

Two different corn cultivars were compared with their genetically modified counterparts containing the gene coding for the Cry1A(b) protein of Bacillus thuringiensis (Bt). There were no analytical differences between the conventional and transgenic genotype kernels, whereas stovers from Bt⁺ plants had higher sugar (148.3 g kg^?1 versus 115.9 g kg^?1; P < 0.01) and lower NDF (592.7 g kg^?1 versus 631.5 g kg^?1; P < 0.05) contents than Bt^? maize. A comparison of the amino acid profiles showed higher phenylalanine content in kernels from the Bt⁺ plants (49.1 g kg^?1 vs 47.8 g kg^?1; P < 0.05) which was, however, not reflected in the protein content. The initial dry matter rumen degradability of the isogenic kernels was higher than that of Bt⁺ varieties (569.5 g kg^?1 vs 543.7 g kg^?1; P < 0.05), whereas the lower fibre content increased the dry matter (548.6 g kg^?1 vs 526.6 g kg^?1; P < 0.01) and protein (695.6 g kg^?1 vs 647.9 g kg^?1; P < 0.01) degradability after 24 h of incubation in stovers from Bt⁺ plants. The NDF degradability was higher in Bt^? corn varieties because of the higher proportion of hemicellulose in the total fibre. Copyright © 2003 Society of Chemical Industry     

Nutrient utilisation in response to dietary supplementation of chicory inulin in growing pigs

The digestive and post‐absorptive utilisation of dietary crude protein (CP), calcium (Ca) and phosphorus (P) in response to dietary supplementation of chicory inulin extract was investigated with six Yorkshire barrows with an average initial body weight of 30 kg. The barrows were fed a corn (maize) and soybean meal‐based diet containing 0 or 50 g kg^?1 chicory inulin extract according to a two‐period crossover design. The digestive utilisation of CP, Ca and P did not differ (P > 0.05) between the control and the inulin‐fed pigs. Furthermore, the post‐absorptive urinary loss of CP and Ca was not affected (P > 0.05) by 50 g kg^?1 chicory inulin supplementation. However, inulin supplementation improved post‐absorptive P utilisation through a reduction (P = 0.01) in urinary P loss by 1.6 percentage units compared with the control group. In conclusion, dietary supplementation of 50 g kg^?1 chicory inulin does not affect dietary CP and Ca utilisation but does reduce urinary P loss in growing pigs. Copyright © 2004 Society of Chemical Industry     

Nutritional value of animal feed grade wheat as replacement for maize in lamb feeding for mutton production

The utilization of abundantly available animal feed grade wheat (AFW) as a replacement for conventional and costly cereal supplement in lamb feeding to lower the cost of mutton production was explored. Thirty‐five growing lambs divided into five equal groups and were fed diets containing 0, 118, 235, 353 or 470 g kg^?1 AFW replacing equal quantity of maize. The diets were fed in the form of composite feed mixture, which had a roughage (Prosopis cineraria leaves) to concentrate ratio of 25:75. Dry matter intake (DMI) was not different in these groups, ranging from 35 to 42 g kg^?1 body weight, while AFW inclusion linearly (P < 0.05) reduced DMI. The digestibility coefficients of dry matter (DM), organic matter (OM), crude protein (CP) and cellulose were not affected by AFW addition, whereas neutral detergent fibre and acid detergent fibre digestibility coefficients were reduced (P < 0.05). The digestible CP content (142.7–162.7 g kg^?1 diet) increased (P < 0.01) linearly with increased AFW inclusion levels. However, AFW additions did not affect metabolizable energy (ME) value of diet (10.2–10.5 MJ kg^?1 diet DM). Digestible CP intake was similar but digestible DM and OM intake tended to decrease (P < 0.05) linearly when expressed in terms of g kg^?1 W^0.75. ME intake (MJ d^?1) was not different among the diets but showed linear (P = 0.041) reducing trends with increasing AFW levels in diet. The efficiency of ME and N utilization for unit gain was also not affected by AFW incorporation. N retained as g d^?1, percentage of intake and percentage of absorbed ranged from 15.4 to 19.5 g, 49.7% to 60.3% and 62.6% to 74.6%, respectively. Intake and utilization of dietary N was not affected but urinary N excretion reduced (P < 0.05) linearly by AFW. Daily microbial N (MN) flow estimated by urinary purine derivative excretion was significantly (P < 0.01) higher for lambs fed a diet with AFW 235 g kg^?1 (3.05 g MN) and 353 g kg^?1 (2.51 g MN) compared to without AFW diet (1.31 g MN). MN when expressed as g kg^?1digestible organic matter intake (DOMI) and microbial protein g kg^?1 digestible organic matter apparently fermented in rumen (DOMR) followed a similar trend. During the growth trial, lambs fed diets containing AFW (353 g kg^?1), which replaced 75% maize had higher total gain (14 kg, P < 0.05) and average daily gain (ADG 154 g, P < 0.05). However, feed efficiency (feed consumed kg^?1 live weight gain) was not different. Rumen pH and microbial enzyme activities studied 4 h post feeding revealed that AFW did not affect rumen pH, which ranged from 5.95 to 6.30. Similarly, carboxymethyl cellulase and β‐xylosidase enzyme activities were not different among treatments, but AFW inclusion linearly (P = 003) increased carboxymethyl cellulase enzyme activities. The α‐amylase enzyme activity differed significantly (P < 0.05) and was highest (22.6 IU) in groups where AFW replaced maize completely. It was concluded that, in lambs reared under intensive system for mutton production on high concentrate diets, conventional and costly energy supplements like maize can be replaced up to 75% with a low‐cost animal feed grade wheat to economize on cost of production. However, more studies are required to confirm these inclusion levels for greater economic returns. Copyright © 2007 Society of Chemical Industry     

Chemical composition,antinutritional constituents,precaecal crude protein and amino acid digestibility in three unconventional tropical legumes in broilers

Three tropical crop seeds, namely Enterolobium cyclocarpum, Mucuna pruriens and Centrosema pubescens, were assessed for their contents of chemical constituents, antinutritional factors (ANFs), crude protein (CP) and amino acid (AA) digestibility. Their meals were incorporated into broiler diets in place of maize starch at two levels (150 and 300 g kg^?1). Four hundred and twenty 1‐day‐old broilers were randomly assigned to seven experimental diets on a weight basis and used to determine CP and AA digestibility in the diets and seeds, and performance of the birds. The CP contents were 237, 278 and 252 g kg^?1 DM in E. cyclocarpum, M. pruriens and C. pubescens, respectively. Compared to the basal diet, the digestibility of CP and AAs in the diets and seeds was significantly (p < 0.05) reduced at higher level of inclusion of E. cyclocarpum and M. pruriens but increased at higher C. pubescens inclusion. Digestibility of arginine, threonine and lysine in the C. pubescens meal diets was similar to that in the basal diet. Digestibility values of CP and AAs were least in E. cyclocarpum. Aspartic acid was the least and glutamic acid the most digested AA in all the seeds. Among the essential AAs, threonine was the least digested AA, while leucine (in E. cyclocarpum and M. pruriens) and lysine (in C. pubescens) had the highest digestibility with values of 65, 73 and 72%, respectively. Feed intake, body weights and weight gain in the birds were significantly (P < 0.05) reduced in the E. cyclocarpum and M. pruriens diets but increased in the C. pubescens diets compared to the basal diet. Results of the study suggest that, based on the CP content and AA profiles in the seeds, they have potential for poultry feeding. The presence of ANFs, especially in E. cyclocarpum and M. pruriens, however, could be a major limitation in their use in poultry feeding. Copyright © 2006 Society of Chemical Industry     

Effect of temperature and time during steam treatment on the protein quality of full-fat soybeans from different origins

Soybeans (Glycine max) of Argentinian and Chinese origin were steam-processed at 102°C, 118°C and 136°C for various durations with the use of a laboratory-scale steam toaster. Samples of raw and processed soybeans were analysed for dry matter (DM), crude protein (CP), trypsin inhibitor activity (TIA), protein dispersibility index (PDI) and reactive lysine content. Chinese raw soybeans showed higher levels of CP, TIA and PDI, and a lower level of reactive lysine than Argentinian raw soybeans (366 vs 357 g kg⁻¹, 20.6 vs 15.2 mg g⁻¹, 87.6 vs 85.6% and 17.4 vs 19.4 g kg⁻¹, respectively). Both the TIA and PDI of the two soybean samples were decreased following a logarithmic pattern with the lengthening of the heating time when beans were steam heated at various temperatures. The reduction rates for TIA and PDI, however, were different between the two origins of soybeans. Chinese soybeans required a longer time or a higher temperature to reduce their TIA to a safe level in comparison with Argentinian soybeans. In the case that the beans were heated at 136°C, the difference in PDI between Chinese and Argentinian soybeans was smaller. It is concluded that the two soybeans origins need different processing conditions to improve their protein properties. © 1998 SCI.     

Nutritional value of feed grade chickpeas for ruminants and pigs

The feeding value of feed grade chickpeas (Kabuli and Desi type) for ruminants and pigs was determined in two studies. Two ruminally fistulated cows were used in the first study to determine the effects of moist heat treatment (127 °C for 10 min) on the ruminal protein degradability of feed grade chickpeas. Heat treatment reduced (P < 0.05) soluble crude protein and increased (P < 0.05) the amount of crude protein associated with neutral detergent fibre for both types of chickpeas. Ruminal degradability of crude protein for Kabuli and Desi chickpeas was reduced by 39 and 33% (P < 0.05) respectively as a result of heating. In the second study, 64 crossbred pigs were each assigned to one of four dietary treatments in a factorial (4 treatments × 2 sexes) design experiment. The experimental barley/wheat‐based diets were supplemented with either soybean meal (control), Kabuli chickpeas (300 g kg⁻¹), Desi chickpeas (300 g kg⁻¹) or field peas (300 g kg⁻¹). Dry matter and gross energy digestibility coefficients, determined using the indicator method, were lower (P < 0.05) for the Desi‐ than for the Kabuli‐supplemented diet. However, no differences were observed in dry matter or gross energy digestibility between the Kabuli chickpea‐supplemented diet and the control or the field pea‐supplemented diet. Diets supplemented with chickpeas or field peas had a lower (P < 0.05) crude protein digestibility than the control diet. Pigs fed either of the chickpea‐supplemented diets during the growing phase gained less (P < 0.05) than pigs fed the control diet. However, during the finishing phase and over the entire experiment, dietary treatment had no effect on pig performance. There were no significant differences in carcass traits between pigs fed any of the four diets. It was concluded that moist heat treatment is an effective method to increase the rumen escape protein value of chickpeas and that the inclusion of feed grade Kabuli or Desi chickpeas in finishing diets up 300 g kg⁻¹ had no detrimental effects on pig performance. © 2000 Society of Chemical Industry     

Potential protein degradation balance and total metabolizable protein supply to dairy cows from heat‐treated faba beans

The effects of pressure toasting (100, 118 and 136 °C for 3, 7, 15 and 30 min) on potential protein nutritional value of faba beans were evaluated with the NRC 2001 dairy model, by determining undegraded (RUP) and degraded rumen protein (RDP), undegraded (RUST) and degraded rumen starch (RDST), truly absorbed undegraded protein (ARUP), microbial protein (MCP_RDP) synthesized in the rumen from rumen‐available protein, truly absorbed rumen synthesized microbial protein (AMCP), truly absorbed rumen endogenous protein (AECP), total metabolizable protein (MP) in the small intestine, and the protein degradation balance (PDB). The treatments increased RUP, RUST, ARUP and MP (p < 0.001), and decreased RDP, RDST, MCP_RDP and PDB (p < 0.001), the effects increasing with increasing temperature and time. The treatments increased (p < 0.001) ARUP without affecting AECP and AMCP, so that the net absorbable total MP in the small intestine was increased. The PDB was reduced (p < 0.001) but never became negative. These results indicated that potential microbial protein synthesis would not be impaired due to sufficient nitrogen in the rumen, but the high positive PDB values with most treatments, except 136 °C for 15 min (PDB 2.0 g kg^?1 DM) indicated that there were large potential losses of nitrogen in the rumen, particularly for the control with a value of 88.9 g kg^?1 dry matter. It is concluded that predicted potential protein degradation balance and total metabolizable protein supply from faba beans were improved by the treatments. Copyright © 2005 Society of Chemical Industry     

Effect of increasing dietary protein with constant lysine:methionine ratio on production and omasal flow of nonammonia nitrogen in lactating dairy cows

Eight lactating cows were fed 4 diets in which dietary crude protein (CP) was increased in steps of approximately 2 percentage units from 11 to 17% of DM by replacing high-moisture corn with soybean meal supplemented with rumen-protected Met to maintain a Lys:Met ratio of 3:1 in metabolizable protein. Trial design was a replicated 4 × 4 Latin square; experimental periods lasted 28 d, with data and sample collection being performed during wk 3 and 4 of each period. Digesta samples were collected from the rumen as well as the omasum to measure metabolite concentrations and ruminal outflow of N fractions using infusion of ¹⁵N-enriched ammonia to quantify microbial nonammonia N (NAN) and nonmicrobial NAN. Data were analyzed using the MIXED procedure of SAS (SAS Institute Inc.). There were linear increases in the yields of milk and true protein and concentration of milk urea N, and a linear decrease in N efficiency, with increasing dietary CP. Apparent ruminal and total-tract N digestibility increased linearly with increasing dietary CP, but estimated true total-tract N digestibility was not affected. Apparent digestibility of the other macronutrients was not influenced by diet. Ruminal ammonia, total AA and peptides, and branched-chain VFA also increased linearly with dietary CP. The ¹⁵N enrichment of liquid- and particle-associated microbes linearly declined with increasing dietary CP due to decreasing ¹⁵N enrichment of the ammonia pool. Although no effect of dietary CP on nonmicrobial NAN flow was detected, total NAN flow increased linearly from 525 g/d at 11% CP to 637 g/d at 17% CP due to the linear increase in microbial NAN flow from 406 g/d at 11% CP to 482 g/d at 17% CP. Under the conditions of this study, when dietary CP was increased by adding soybean meal supplemented with rumen-protected Met, improved milk and protein yields were driven not by RUP supply but by increased ruminal outflow of microbial protein.     

Wet‐fractionation of Phaseolus lunatus seeds: partial characterization of starch and protein

The optimum extraction conditions for integral use of Phaseolus lunatus seed, in alkaline medium, are 1:6 (w/v) flour:water ratio, pH 11 and a 1 h extraction time. Three main fractions were produced under these conditions: starch; protein isolate and fibrous residue by‐product. The yield is 288.4 g kg^?1 starch, 188.2 g kg^?1 protein isolate and the remaining quantity, fibrous residue. The starch has 98.4% purity, a 75 °C gelatinization temperature and high syneresis even at high concentrations. It also has high viscosity, good stability and middle retrogradation during the heating–cooling cycle. The protein isolate contains 711.3 g kg^?1 protein as well as 75.5 g lysine kg^?1 protein, 10.1 g methionine kg^?1 protein and 12.2 g tryptophan kg^?1 protein. Its in vitro digestibility is 79% with a 2.5 c‐PER. The fibrous residue contains 63 g kg^?1 of protein, 328.4 g kg^?1 of crude fiber and 567.3 g kg^?1 of NFE. Copyright © 2004 Society of Chemical Industry     

A meta-analysis of the effects of dietary protein concentration and degradability on milk protein yield and milk N efficiency in dairy cows

Data sets from North American (NA, 739 diets) and North European (NE, 998 diets) feeding trials with dairy cows were evaluated to investigate the effects of dietary crude protein (CP) intake and ruminal degradability on milk protein yield (MPY) and efficiency of N utilization for milk protein synthesis (MNE; milk N ÷ N intake) in dairy cows. The NA diets were based on corn silage, alfalfa silage and hay, corn and barley grains, and soybean meal. The NE diets were based on grass silage, barley and oats grains, and soybean and rapeseed meals. Diets were evaluated for rumen-degradable and undegradable protein (RDP and RUP, respectively) concentrations according to NRC (2001). A mixed model regression analysis with random study effect was used to evaluate relationships between dietary CP concentration and degradability and MPY and MNE. In both data sets, CP intake alone predicted MPY reasonably well. Addition of CP degradability to the models slightly improved prediction. Models based on metabolizable protein (MP) intake predicted MPY better than the CP or the CP-CP degradability models. The best prediction models were based on total digestible nutrients (TDN) and CP intakes. Similar to the MPY models, inclusion of CP degradability in the CP (intake or concentration) models only slightly improved prediction of MNE in both data sets. Concentration of dietary CP was a better predictor of MNE than CP intake. Compared with the CP models, prediction of MNE was improved by inclusion of TDN intake or concentration. Milk yield alone was a poor predictor of MNE. The models developed from one data set were validated using the other data set. The MNE models based on TDN and CP intake performed well as indicated by small mean and slope bias. This meta-analysis demonstrated that CP concentration is the most important dietary factor influencing MNE. Ruminal CP degradability as predicted by NRC (2001) does not appear to be a significant factor in predicting MPY or MNE. Data also indicated that increasing milk yield will increase MNE provided that dietary CP concentration is not increased, but the effect is considerably smaller than the effect of reducing CP intake.     

Effect of feed intake level on ileal digestibilities of crude protein and amino acids in diets for piglets

BACKGROUND: The study was conducted to determine the effect of graded levels of feed intake on apparent (AID) and standardized (SID) ileal digestibilities of crude protein (CP) and amino acids (AA) in diets for piglets. The piglets were surgically fitted with simple T‐cannulas at the distal ileum. The cornstarch–casein–soybean meal‐based diets were fed at three graded levels of feed intake corresponding to 30, 45 and 60 g kg^?1 body weight (BW) per day. RESULTS: The AID and SID of most AA were quadratically affected by the feed intake level (P?0.05). Initially, both AID and SID of most AA increased up to 1.9 percentage units as the feed intake level was increased from 30 to 45 g kg^?1 BW. Thereafter, these AID and SID values decreased by 2.6 and 2.7 percentage units, respectively, as the feed intake level was further increased from 45 to 60 g kg^?1 BW. CONCLUSION: Because the voluntary feed intake is highly variable in piglets after weaning, comparison of ileal AA digestibilities between and within studies may be confounded by variations in feed intake level. Thus, when designing digestibility studies with piglets, a standardization of feed intake should be taken into consideration. Copyright © 2011 Society of Chemical Industry     

Low‐protein amino acid‐supplemented diets in broiler chickens: effects on performance,carcass characteristics,whole‐body composition and efficiencies of nutrient utilisation

Two concurrent trials were conducted to investigate the influence of low‐protein amino acid‐supplemented diets on the performance, carcass characteristics, whole‐body composition and efficiencies of nutrient utilisation by the male broiler chicken from age 3 to 6 weeks. The first trial comprised five isoenergetic (13.0 MJ kg⁻¹) diets containing 225 (control), 210, 190, 172 or 153 g kg⁻¹ crude protein (CP) supplemented with essential amino acids (EAAs) to meet the minimum National Research Council recommendations. In the second trial a composite mixture of non‐essential amino acids (NEAAs) was added to the lower‐CP diets (ie 210–153 g kg⁻¹) such that they became isoproteinous (N × 6.25) with the 225 g kg⁻¹ control. Neither the lowering of dietary CP nor NEAA supplementation had any significant influence on weight gain or the relative weights of the various carcass cuts. However, chicks fed the lowest‐CP diets consumed more feed (P ≤ 0.05) and had poorer (P ≤ 0.05) feed conversion efficiency (FCE). NEAA supplementation enhanced FCE to the control levels. Whole‐body compositional analysis showed that lowering dietary CP increased (P ≤ 0.01) total body fat in a linear fashion (P ≤ 0.001; r = −0.72). Equalising dietary CP with the control (ie maintaining identical energy/protein ratio) by NEAA supplementation did not correct for the fat deposition. Total body protein (g kg⁻¹) was identical with the control with or without NEAA supplementation. Dietary energy, protein retention efficiency (PRE) and protein efficiency ratio (PER) were more efficient (P ≤ 0.01) in the lower‐protein diets, while NEAA supplementation significantly (P ≤ 0.01) decreased the efficiency of N utilisation. Reducing dietary CP from 225 to 153 g kg⁻¹ decreased N excretion in a highly significant linear fashion (P ≤ 0.001; r = 0.73). The nutritional and environmental implications of the increased body fat deposition on the one hand and the decreased N excretion on the other in the low‐protein‐fed chickens are discussed and the need to harmonise these apparently conflicting interests is emphasised. © 2000 Society of Chemical Industry     

Microbial protein synthesis, nitrogen capture efficiency and nutrient utilisation in sheep fed on finger millet straw (Eleucine coracana)-based diet with different rumen-degradable nitrogen levels

BACKGROUND: Microbial protein synthesised in the rumen is a very important protein source for ruminants. It is essential to provide an adequate amount of rumen‐degradable nitrogen (RDN) for optimum microbial protein synthesis in the rumen on straw‐based diets. The objective of this study was to determine the RDN requirement for optimum microbial protein synthesis (MPS), nitrogen capture efficiency (NCE) and nutrient utilisation in Nellore rams fed on a finger millet straw (FMS)‐based diet. RESULTS: Thirty‐six Nellore sheep were randomly divided into four groups of nine animals each using a balanced, completely randomised design. The animals in group 1 (RDN0) were fed with ad libitum FMS. Those in groups 2, 3 and 4 (RDN1, RDN2 and RDN3) were supplemented with groundnut cake to provide RDN levels of 14, 18 and 23 g RDN kg^?1 digestible organic matter intake (DOMI) or 21, 27 and 35 g RDN kg^?1 digestible organic matter apparently digested in the rumen (DOMR) respectively along with FMS. The digestibility coefficients of all nutrients and MPS increased (P < 0.05) quadratically with increasing level of RDN supplementation. NCE decreased linearly (P < 0.05) as the level of RDN increased. CONCLUSION: The results suggest that 12 g RDN kg^?1 DOMI or 19 g RDN kg^?1 DOMR may be adequate for optimum MPS, NCE and digestibility of nutrients in sheep fed on an FMS‐based diet. Copyright © 2011 Society of Chemical Industry     

Characterisation of the leaf meals,protein concentrates and residues from some tropical leguminous plants

Leaf meals (LMs) from freshly harvested leaves of butterfly pea (Centrosema pubescens), devil bean (Mucuna pruriens), flamboyant flower (Delonix regia), Bauhinia tomentosa, coast wattle (Acacia auriculiformis), quick stick (Glyricidia sepium) and ipil‐ipil (Leucaena leucocephala) were analysed for their nutrient and anti‐nutritional content. Then, leaf protein concentrates (LPCs) were produced from the leaves by fractionation and characterised along with the fibrous residues. On average, the LM contained 181 g kg^?1 dry matter (DM) CP (range: 100–280 g kg^?1 DM), 139 g kg^?1 DM crude fibre (range: 77–230 g kg^?1 DM) and 133 g kg^?1 DM ether extract (range: 86–165 g kg^?1 DM) while the gross energy averaged 17.0 MJ kg^?1. On average, leaf protein fractionation enhanced the CP, ether extract and the gross energy in the LPC by 39.5%, 33.5% and 22.0%, respectively, while the crude fibre of the LMs was reduced by 41%, on average, in the LPCs. Fractionation reduced the mineral content of the leaves generally. The mean phytin content varied from 0.36 g kg^?1 in LPCs to 0.86 g kg^?1 in leaf meal, while the mean phytin‐P content varied from 0.10 g kg^?1 in LPCs to 0.24 g kg^?1 in leaf meal. The total phenol levels in the LMs were reduced by 33.7% in the LPCs, on average. These results suggest that, while the LPCs from these plants could be used as protein supplements in non‐ruminant feeds in regions where there is an acute shortage of plant protein, the LMs or LPC fibrous residues could be fed to ruminant animals. Copyright © 2006 Society of Chemical Industry     

The nutritive value for ruminants of thin stillage and distillers' grains derived from wheat,rye, triticale and barley

A study was conducted to determine nutrient degradabilities of thin stillages and distillers' grains derived from wheat‐, rye‐, triticale‐ and barley‐based ethanol production. In vitro protein degradabilities of wheat, rye, triticale and barley thin stillages were determined using a protease enzyme assay. One ruminally fistulated cow was used to determine ruminal nutrient degradabilities for wheat, rye, triticale and barley distillers' grains. Results of the in vitro study showed that the soluble protein fraction was highest for rye thin stillage and lowest for barley thin stillage. The degradation rate of the slowly degradable protein fraction was higher for wheat and triticale thin stillage than rye thin stillage and was higher for rye than barley thin stillage. Effective degradability of crude protein followed the order rye (659 g kg⁻¹) > triticale (632 g kg⁻¹) > wheat (608 g kg⁻¹) > barley (482 g kg⁻¹) thin stillage. Ruminal degradability of dry matter was highest for rye and lowest for barley distillers' grains. Ruminal degradability of dry matter was also higher for wheat than triticale distillers' grains. Crude protein from barley distillers' grains had a lower ruminal degradability relative to crude protein from wheat and rye distillers' grains. Ruminal degradability of neutral detergent fibre was highest for rye distillers' grains (470 g kg⁻¹), intermediate for wheat and triticale distillers' grains (average 445 g kg⁻¹) and lowest for barley distillers' grains (342 g kg⁻¹). It was concluded that thin stillage and distillers' grains derived from barley had a lower nutritive value for ruminants compared with those derived from wheat, rye and triticale. © 2000 Society of Chemical Industry