Productions and monomer compositions of exopolysaccharides by Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains isolated from traditional home-made yoghurts and raw milk

In this study, a total of forty‐five strains of lactobacilli and streptococci were determined exopolysaccharide (EPS) production in skim milk and Man Rogosa and Sharpe (MRS)/M17 medium, viscosity and proteolytic activity. The exopolysaccharide production by lactobacilli strains during growth in MRS medium was twenty‐one to 211 mg L^?1, while in skim milk was to thirty‐six to 315 mg L^?1. The EPS production by streptococci strains during growth in M17 medium was sixteen to 114 mg L^?1, while in skim milk was to twenty‐four to 140 mg L^?1. The EPS production of strains was lower in MRS/M17 medium than skim milk. Results showed that it was not clear correlation between the viscosity and EPS production of some strains. All strains were shown proteolytic activity. Positive correlations between exopolysaccharide production and proteolytic activity in skim milk were found some strains of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. These results indicated that the high exocellular protease‐producing strains can produce high EPS in skim milk. The monomer compositions of the EPSs formed by selected five strains were analysed. Mannose dominated (99–100%) on the EPS produced by L. delbrueckii subsp. bulgaricus and S. thermophilusstrains (except L. delbrueckii subsp. bulgaricus 22) in skim milk and MRS/M17 medium. Besides, the EPSs of strains in skim milk contained small amount of lactose.     

Comparative study of the polypeptide profiles and functional properties of Sinapis alba and Brassica juncea seed meals and protein concentrates

Defatted meals and protein concentrates from six accessions of Sinapis alba and one accession of Brassica juncea mustard seeds were analysed for their polypeptide profile and functional properties. Two types of protein concentrates were prepared using acid‐induced and calcium‐induced protein precipitations. Meals from the S alba seeds had similar polypeptide composition, which was different from that of the B juncea meal. Non‐reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that two of the major polypeptides (50 and 55 kDa) in S alba seeds were susceptible to acid‐induced precipitation but resistant to calcium‐induced precipitation. The B juncea meal proteins were significantly (p ≤ 0.05) more susceptible to heat coagulation than the S alba meal proteins. Emulsifying activity index was significantly higher (p ≤ 0.05) in the B juncea meal and protein concentrates when compared with similar products from S alba. It was concluded that the presence of a high‐molecular‐weight (135 kDa) disulfide‐bonded polypeptide could have contributed to the lower emulsifying power of the S alba products when compared with the B juncea proteins that do not have this polypeptide. Copyright © 2005 Society of Chemical Industry     

Apparent ileal digestibility of amino acids in feed ingredients determined with broilers and layers

The apparent ileal digestibility of amino acids in eight feed ingredients were determined using broilers and layers. The ingredients included three cereals (wheat, sorghum and maize), one cereal by‐product (wheat middlings), three oilseed meals (canola, cottonseed and soybean meals) and one animal protein meal (meat and bone meal). Dietary protein in the assay diets was supplied solely by the test ingredient. All diets contained 20 g kg^?1 acid‐insoluble ash as an indigestible marker, and each diet was offered ad libitum in mash form to five replicate pens of 42‐day‐old broilers and 60‐week‐old layers. The digestibility coefficients of most amino acids for wheat and sorghum were similar (P > 0.05) in broilers and layers. The digestibility of most amino acids for maize was higher (P < 0.05) in broilers compared to those in layers. The digestibility of individual amino acid for wheat middlings was higher (P < 0.05) in layers than in broilers. In general, the digestibility of amino acids for cottonseed meal, soybean meal, and meat and bone meal were similar (P > 0.05) between broilers and layers. The influence of class of bird on digestibility in canola meal was variable. The digestibility of threonine, valine, isoleucine, leucine, phenylalanine, glutamic acid and alanine were higher (P < 0.05), and those of methionine, histidine and lysine were lower (P < 0.05) in broilers compared to layers. These results suggest that the practice of using amino acid digestibility values generated with broilers for layers may not be appropriate for all feed ingredients. Copyright © 2006 Society of Chemical Industry     

Acetyldiaminobutanoic acid,a potential lathyrogenic amino acid in leaves of Acacia angustissima

Acacia angustissima has potential in agroforestry systems for forage production in tropical environments. However, feeding trials indicate that the leaves are potentially toxic. Signs of toxicity in sheep are similar to those presented by sheep fed flatpea (Lathyrus sylvestris) hay which contains a high concentration of the non‐protein amino acid 2,4‐diaminobutanoic acid (DABA). Cation exchange chromatography, high‐performance liquid chromatography (HPLC) and NMR were used to isolate and identify the non‐protein amino acid in A angustissima leaves. A quantitative HPLC method was used to determine the content of the non‐protein amino acid in leaves from 20 accessions. The non‐protein amino acid was identified as 4‐N‐acetyl‐2,4‐diaminobutanoic acid (ADAB), previously reported to occur in seeds. The average and range in ADAB content were 16.8 and 10.6–25.4 mg g^?1 respectively. This content of ADAB is higher than the levels of DABA in flatpea hay that are toxic to sheep. © 2001 Society of Chemical Industry     

Comparison of proximate composition,amino acid and fatty acid profiles in wild,pond‐ and cage‐cultured longsnout catfish (Leiocassis longirostris)

The proximate composition, amino acid and fatty acid profiles in the fillets of wild, pond‐ and cage‐cultured longsnout catfish (Leiocassis longirostris) were determined to identify nutritional differences. Wild fish showed higher (P < 0.05) moisture and viscerosomatic index (VSI), but lower (P < 0.05) protein, ash and gross energy than cage‐cultured fish. Pond‐cultured fish contained lower (P < 0.05) protein and ash contents, but higher VSI compared to cage‐cultured fish. The amino acid of glycine content was higher (P < 0.05) in wild fish than in pond‐ and cage‐cultured fish. Most of the fatty acids had a significant difference among all fish groups. The percentages of total polyunsaturated fatty acids (∑ PUFAs) were higher (P < 0.05) in wild and pond‐cultured fish than in cage‐cultured fish. Pond‐cultured fish had higher (P < 0.05) ∑ n‐3 PUFAs, eicosapentaenoic acid (EPA), docosahxaenoic acid (DHA) and ∑ n‐3/∑ n‐6 PUFAs ratio than wild and cage‐cultured fish. The differences among the wild, pond‐ and cage‐cultured fish may be attributed to dietary components and environmental conditions of the fish.     

Isolation and identification of exopolysaccharide producer lactic acid bacteria from Turkish yogurt

Lactic acid bacteria (LAB) were isolated from traditional yogurt samples and genotypic characterization of these isolates revealed the presence of 21 distinct LAB strains belonging to Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus, Leuconostoc mesenteroides, and Lactobacillus plantarum as new LAB strains. Determination of the exopolysaccharide (EPS) production characteristics of the selected strains of each species revealed that all strains possessed at least one gene required for both homopolymeric‐ and heteropolymeric‐type EPS production. Structural analysis of the EPSs showed that L. delbrueckii subsp. bulgaricus Y39 and S. thermophilus Y102 produced heteropolymeric EPS containing glucose and galactose, whereas Leuc. mesenteroides Y35 and L. plantarum Y36 produced homopolymeric glucan‐type EPS. The level of EPS production in these strains was found to be in a similar range. These strains with EPS production characteristics are good candidates for future studies as new LAB for yogurt production.

Practical applications

Recent trends in yogurt production technology have led to an increased use of ropy starter cultures in yogurt production due to the technological roles of exopolysacharides (EPS) produced by these cultures. The main role of EPS in yogurt production is to improve the textural properties of yogurt as an in situ produced natural polymer. In addition to the yogurt starter cultures, use of adjunct cultures during production of yogurt is also of special interest to enhance the technological and nutritional characteristics of yogurt. Therefore, in this study, potential yogurt starter and adjunct cultures from traditional yogurt samples with EPS production characteristics were isolated. From these isolates, Lactobacillus delbrueckii subsp. bulgaricus Y39 and Streptococcus thermophilus Y102 produced heteropolymeric EPS containing glucose and galactose, whereas Leuconostoc mesenteroides Y35 and Lactobacillus plantarum Y36 produced homopolymeric glucan.     

Chemical characteristics and antioxidant activities of polysaccharide purified from the seeds of Plantago asiatica L.

BACKGROUND: A water‐soluble polysaccharide from the seeds of Plantago asiatica L. (P. asiatica L. polysaccharide, PLP) was extracted with hot water and purified by gel filtration chromatography. The chemical characteristics of PLP were determined by high‐performance gel permeation chromatography (HPGPC) and Fourier transform infrared (FTIR) spectroscopy. In addition, the antioxidant activities of PLP in vitro were evaluated using various test systems, including scavenging of 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) radicals, scavenging of superoxide radicals generated by 1,2,3‐phentriol autoxidation, scavenging of hydroxyl radicals and inhibition of lipid peroxidation. RESULTS: The molecular weight of PLP was determined by HPGPC to be about 1894 kDa. PLP contained 29.2 g kg^?1 protein and 145.8 g kg^?1 uronic acid. The FTIR spectrum of PLP also revealed typical characteristics of a polysaccharide containing protein and uronic acid. Moreover, the results showed that PLP possessed antioxidant activities, but lower than those of ascorbic acid. CONCLUSION: PLP is an acid protein‐bound polysaccharide of high molecular weight, but its structure needs further study. The present results suggest that PLP could potentially be used as a natural antioxidant. Copyright © 2009 Society of Chemical Industry     

Effect of the duration of feeding of a protein‐free diet on endogenous ileal nitrogen and amino acid loss in the growing pig

The aim of the study was to determine whether endogenous nitrogen and amino acid excretions at the terminal ileum change over time in the growing pig fed a protein‐free diet for 8 days. Seven entire male pigs with an overall mean live weight of 81.6 kg (SEM 3.3 kg) and surgically implanted post‐valve T caecum cannulas were fed a semi‐synthetic casein‐based diet for 8 days. Food was withheld from the pigs for 24 h, after which they were fed a protein‐free diet for a further 8 days at a rate of 10% of metabolic body weight per day. Chromic oxide was included in the protein‐free diet as an indigestible marker. Ileal digesta were collected continuously from 13:00 to 18:00 h on each day of the experimental period. Endogenous ileal nitrogen flows were determined for each pig each day the protein‐free diet was given, and endogenous ileal amino acid flows for the first and eighth days. There were no significant (P > 0.05) effects of the duration of feeding of the protein‐free diet on endogenous ileal total nitrogen or amino acid flows, except for the amino acids glycine and cysteine, the flows of which significantly decreased over the 8 day period (P < 0.01 and P < 0.05 for glycine and cysteine respectively), from (mean ± SEM) 1639 ± 217 to 892 ± 212 µg g⁻¹ dry matter intake (DMI) for glycine and from 173 ± 13 to 127 ± 19 µg g⁻¹ DMI for cysteine. The relative contributions (moles of each amino acid as a proportion of total moles of amino acids) of threonine, glycine and cysteine decreased significantly (P < 0.05) and that of proline increased significantly (P < 0.05) during the 8 days that the protein‐free diet was fed to the pigs. © 2000 Society of Chemical Industry     

Forage quality and tannin concentration and composition of a collection of the tropical shrub legume Flemingia macrophylla

A collection of 23 Flemingia macrophylla (Willd.) Merrill accessions of different growth habits and contrasting digestibility and one Flemingia stricta reference accession were assessed for forage quality with particular emphasis on digestibility, condensed tannin concentration and fiber content. Large differences in in vitro dry matter digestibility (IVDMD) (356 to 598 g kg^?1), content of crude protein (CP) (121 to 254 g kg^?1) and extractable condensed tannins (CT) (0 to 268 g kg^?1), protein‐binding capacity of extractable CT or astringency (1.7 to 7.9 protein‐binding entities) (PBE) and monomer composition of extractable CT were detected. IVDMD and extractable CT were negatively correlated and extractable CT was positively correlated with protein‐binding capacity. Prodelphinidin was positively and propelargonidin negatively correlated with protein‐binding capacity of extractable CT. The accessions CIAT 18438, CIAT 21083, CIAT 21090 and CIAT 22082 were superior to the most widely used accession CIAT 17403 in terms of forage quality and could be an option in production systems with acid infertile soils. In future evaluations, particular attention needs to be paid to chemical and structural features related to the composition of extractable CT and their effect on nitrogen utilization by ruminants. Copyright © 2006 Society of Chemical Industry     

Effects of season on proximate and fatty acid compositions of two mediterranean fish – the round herring (Etrumeus teres) and tub gurnard (Chelidonichthys lucernus)

The aim of this work was to study the seasonal variation of the proximate and fatty acid compositions in the round herring (Etrumeus teres) and tub gurnard (Chelidonichthys lucernus) caught from the North‐Eastern Mediterranean Sea. Proximate compositions and fatty acid contents of both fish species showed statistically significant seasonal variations (P < 0.05). While the protein contents were at its highest in winter, the lipid contents were at its highest in autumn. The main fatty acids were C16:0 (palmitic acid), C18:0 (stearic acid), C16:1 n‐7 (palmiteoleic acid), 18:1 n‐9c (oleic acid), C20:5 n‐3 (eicosapentaenoic acid) and C22:6 n‐3 (docosahexaenoic acid). The total polyunsaturated fatty acid in round herring was highest in winter, whereas that in tub gurnard was highest in spring.     

Digestive utilisation of protein and amino acids from raw and heated lentils by growing rats

The effect of autoclave treatment on the digestive utilisation of protein and amino acids from lentils was studied in growing rats. Twenty 3‐week‐old Wistar rats (mean live weight 59 ± 4.8 g) were fed two experimental diets (n = 10 rats per diet) consisting of raw lentils (Lens culinaris M, var vulgaris, cv magda‐20) (diet RL) or lentils autoclaved at 120 °C and 1 atm for 30 min (diet AL). An additional group of 10 animals was fed a low‐protein (4%) diet and used to estimate metabolic nitrogen and amino acid excretion. Autoclaving caused a 76% reduction in the levels of trypsin inhibitor activity, but failed to improve the faecal digestive utilisation of protein or total amino acids. Lowest essential amino acid true digestibility in diets RL and AL was found for cysteine (60.2 vs 60.1%) and methionine (68.9 vs 66.6%). The protein digestibility‐corrected amino acid score was 71.2 and 66.4% and the availability of sulphur amino acid‐corrected amino acid score was 57.1 and 52.1% for diets RL and AL respectively. Sulphur amino acids were the first limiting ones. Overall, autoclave treatment did not improve protein or total amino acid digestibility from lentils, but caused a significant improvement in leucine and lysine digestibility and a significant decrease in the digestive utilisation of tyrosine and methionine. © 2002 Society of Chemical Industry     

Effects of peptidase inhibitors and other additives on fermentation and nitrogen distribution in perennial ryegrass silage

The effects of formic acid, three concentrations of formaldehyde in a formic acid/formaldehyde mixture and cysteine‐peptidase inhibitors, 1‐trans epoxysuccinyl‐leucylamido‐(4‐guanidino) butane (E‐64), N‐ethylmaleimide and cystamine on nitrogen (N) distribution during ensilage of perennial ryegrass (Lolium perenne) were investigated. A third cut or perennial ryegrass (163 g dry matter kg⁻¹ and 61 g water‐soluble carbohydrate kg⁻¹ dry matter) was ensiled in two silo sizes; formaldehyde‐treated herbage was ensiled only in larger silos (500–550 g herbage) and cysteine‐peptidase inhibitor‐treated herbage only in smaller silos (130–150 g herbage). Control silages were poorly fermented but contained low concentrations of butyric acid and ammonia N indicating little activity of spoilage bacteria. Formic acid increased peptide N concentrations (P<0.01) in silage from smaller silos but had little effect on other N constituents; in the larger silos, formic acid reduced soluble non protein nitrogen (NPN) and ammonia‐N concentrations and increased peptide N concentrations. Increments in formaldehyde reduced silage soluble and ammonia N concentrations (linear effect; P<0.001). N‐Ethylmaleimide and E‐64 reduced soluble NPN concentrations (P<0.05) but had little effect on other N constituents. Cystamine, however, increased silage peptide N concentrations. Gel filtration on Sephadex G‐25 of silage juice prepared from control and formic acid‐treated silages suggested that most silage peptides were small, with molecular weights of less than 520 Da. © 1999 Society of Chemical Industry     

Purification and characterisation of an acid protease from the Aspergillus hennebergii HX08 and its potential in traditional fermentation

A protease AP3 from Aspergillus hennebergii HX08 was purified by ammonium‐sulphate precipitation, followed by anion‐exchange chromatography and gel filtration. The molecular weight of acid protease AP3 was 33 kDa (SDS‐PAGE and MALDI‐TOF‐MS). The protease AP3 was identified as an acid protease with MALDI‐TOF/TOF tandem MS. Its optimal temperature and pH were 60°C and 4.0, respectively. Its K _max and V _max were 57.92 mg/mL and 32.57 U/mL, respectively. The enzyme was active over a broad pH and temperature range (pH 3.0–5.0 and 30–60°C), and exhibited high activity and stability in 2–12% (v /v) ethanol solvent. Subsequent studies suggest that the enzyme presents a relatively high substrate affinity to wheat protein (98% of total activity). Its application to solid‐state fermentation of wheat flour with Saccharomyces cerevisiae could increase the hydrolysis degree of wheat protein (28.26%) and amino acid nitrogen concentration of fermented grains (34.21%). Additionally, enhanced S. cerevisiae biomass (37.09%) and alcohol concentration (38.29%) were also observed during the process. Volatile compounds analysis of fermented grains by headspace solid‐phase micro‐extraction and GC‐MS revealed more flavour compounds. These results suggest its potential in food and alcohol industries. Copyright © 2017 The Institute of Brewing & Distilling     

Ileal digestibility of defatted soybean,lupin and chickpea seed meals in cannulated Iberian pigs: I. Proteins

Five castrated male Iberian pigs (100 ± 2 kg body weight) fitted with T‐shaped cannulas at the terminal ileum were used to determine ileal digestibility of legume seed meals. The diets were based on defatted soybean, lupin or chickpea seed meals and contained similar levels of digestible energy (14.2–15.1 kJ g^?1) and protein (107 g kg^?1). Protein‐free and a hydrolysed casein diets were used to study endogenous ileal amino acid flows. Chromium oxide (10 g kg^?1 diet) was added to the diets as an indigestible marker. Ileal flows in pigs fed the hydrolysed casein diet were different (p < 0.05) in amino acid contents and composition from those on the protein‐free diet. Ileal sialic acid flows in pigs fed lupin‐ or chickpea‐based diets were higher (p < 0.05) than those of animals fed soybean or casein diets. Among essential amino acids, only the apparent ileal digestibilities of phenylalanine and valine in lupin meal were lower (p < 0.05) than those in soybean. Apparent ileal digestibilities of lupin aspartate and proline, together with chickpea aspartate, were also lower (p < 0.05) than those of soybean. True ileal digestibility of nitrogen in pigs fed lupin or chickpea meals, calculated according to values from animals fed the protein‐free diet, was lower (p < 0.05) than that for soybean or casein. Among individual essential amino acids, only the true ileal digestibility of phenylalanine in lupin was lower (p < 0.05) than that in soybean. True ileal digestibility of nitrogen calculated according to values obtained with pigs fed a hydrolysed casein diet was not different among soybean, lupin or chickpea meals. Among essential amino acids, only the true ileal digestibilities of isoleucine and lysine in chickpea were lower (p < 0.05) than those of soybean. It is concluded that true ileal nitrogen and amino acid digestibilities of lupin and chickpea meals are comparable to those of defatted soybean in Iberian pigs. The results with protein‐free diets tended to underestimate endogenous protein secretion in pigs fed on diets containing protein. Copyright © 2005 Society of Chemical Industry     

Chemical composition and nutritional quality of sea cucumbers

BACKGROUND: The dried form of sea cucumbers has been a seafood and medicinal cure for Asians over many centuries. In this study the chemical composition and nutritional quality of eight common sea cucumbers (Stichopus herrmanni, Thelenota ananas, Thelenota anax, Holothuria fuscogilva, Holothuria fuscopunctata, Actinopyga mauritiana, Actinopyga caerulea and Bohadschia argus) were determined. RESULTS: All species except T. anax and A. caerulea had higher protein and lower fat levels. A. mauritiana and B. argus had less ash content. Glycine was the dominant amino acid found in all species, and content ranged from 126 to 216 mg g^?1 of crude protein. All species exhibited low lysine:arginine ratio and higher essential amino acid scores were obtained by threonine and phenylalanine + tyrosine. A. mauritiana had proportionally less saturated fatty acids (31.23%), and more monounsaturated fatty acids (45.64%) and polyunsaturated fatty acids (PUFA, 23.13%) than other species. Arachidonic acid (C20:4n‐6) was the major PUFA in all species. T. ananas, A. mauritiana and A. caerulea contained more n‐3 PUFA. The n‐3/n‐6 ratios of eight sea cucumbers species ranged from 0.25 to 0.61. CONCLUSION: Sea cucumbers are a seafood with high protein and low fat levels. The amino acid contents were similar but fatty acid profiles were different among species. The comparison showed that T. ananas, A. mauritiana and B. argus possessed higher nutritional values than other sea cucumber species. Copyright © 2010 Society of Chemical Industry     

Relationship between proteolytic changes and tenderness in prerigor lactic acid marinated beef

A meat tenderising procedure involving injection of a lactic acid solution into prerigor muscle was investigated using beef M pectoralis profundus. The distribution of lysosomal enzymes in subcellular fractions, densities of myofibrillar protein bands after SDS‐PAGE and shear force were measured in non‐injected, 0.5 M and 1.0 M lactic‐acid‐injected samples during a 21 days ageing period. The activities of cathepsin B + L and β‐glucuronidase in the soluble fraction increased with level of lactic acid and with time post‐mortem (P < 0.001). Lactic acid and storage decreased densities of SDS‐PAGE bands migrating at the position of myosin heavy chain (MHC) and α‐actinin and increased densities of a 150 kDa band (P < 0.01). SDS‐PAGE of isolated perimysium cleaved with CNBr showed proteolytic cleavage of collagen after prolonged storage. Lactic acid injection significantly reduced shear force (P < 0.001). The cathepsin B + L activity in the soluble fraction correlated to shear force (r = −0.8), the degradation of MHC and α‐actinin (r = −0.88 and −0.90) and the generation of the 150 kDa fragment (r = 0.90) but not to the generation of a 31 kDa fragment (r = 0.05). A major part of the tenderness improvement after lactic acid injection was complete at 24 h post‐mortem, and was therefore due to a rapid process, eg pH‐induced swelling of the muscle structure. The data on enzyme activities and protein degradation, however, suggested that the action of lysosomal cathepsins also contributed to textural changes. © 1999 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     

Sweetpotato (Ipomoea batatas L.) Leaf: Its Potential Effect on Human Health and Nutrition

Previous experiments revealed that sweetpotato leaves contain a high content of polyphenolics, namely anthocyanins and phenolic acids, compared with the major commercial vegetables. Sweetpotato leaves contain at least 15 biologically active anthocyanins that have significant medicinal value for certain human diseases and may also be used as natural food colorants. The anthocyanins were acylated cyanidin and peonidin type. The phenolic acids were composed of caffeic acid (CA) and 5 kinds of caffeoylquinic acid derivatives, 3‐mono‐O‐caffeoylquinic acid (chlorogenic acid, ChA), 3,4‐di‐O‐caffeoylquinic acid (3,4‐diCQA), 3,5‐di‐O‐caffeoylquinic acid (3,5‐diCQA), 4,5‐di‐O‐caffeoylquinic acid (4,5‐diCQA), and 3,4,5‐tri‐O‐caffeoylquinic acid (3,4,5‐triCQA). These polyphenolics showed various kinds of physiological functions, radical scavenging activity, antimutagenic activity, anticancer, antidiabetes, and antibacterial activity in vitro or in vivo, which may be helpful for maintaining and promoting human health. The physiological function of caffeoylquinic acid (CQA) derivatives with the plural caffeoyl group is more effective than with a monocaffeoyl one. This review describes the nutritional composition and physiological functions of sweetpotato leaves when used as a vegetable, and as a resource for products with these functions.     

Antibacterial activity of chitosans with different degrees of deacetylation and viscosities

Antibacterial activities of six acid‐soluble [two degrees of deacetylation (DD) × three viscosities] and two water‐soluble chitosans (two DD with similar viscosities) were examined against eight gram‐negative (Pseudomonas fluorescens, Proteus vulgaris, Erwinia carotovora, Serratia marcescens, Escherichia coli, Vibrio parahaemolyticus, V. vulnificus, and Salmonella Typhimurium) and six gram‐positive bacteria (Listeria monocytogenes, Staphylococcus aureus, Bacillus subtilis, B. cereus, Lactobacillus curvatus, and L. plantarum). Antibacterial activities of chitosans differed depending on the chitosan types and bacteria tested. Water‐soluble chitosans inhibited bacterial growth by one to eight log cycles at 0.1% concentration; however, the effects were much lesser than those observed with 0.05% acid‐soluble chitosans. Minimum inhibitory concentration (MIC) values (0.03% to above 0.1%) of acid‐soluble chitosans were much lower than those (0.05% to above 0.8%) of water‐soluble chitosans. Based on MIC values, the acid‐soluble chitosan with 99% DD and lower viscosity (17.9 mPa s) was most effective in inhibiting bacteria growth among eight chitosans tested.     

Effect of feeding complete feed block containing Prosopis cineraria leaves and polyethylene glycol (PEG)‐6000 on nutrient intake,its utilization,rumen fermentation pattern and rumen enzyme profile in kids

A study was carried out to determine the effect of replacing the cake portion of concentrate mixture with 5 parts polyethylene glycol (PEG)‐6000 in a complete feed block (CFB) containing Prosopis cineraria leaves on the performance, rumen fermentation pattern and rumen enzyme profile of kids under an intensive system of rearing. Eighteen weaners of Sirohi goat of similar body weight (16.0 ± 0.5 kg) and age (90 ± 5 days) were divided into three equal groups. They were housed in individual cages in a side open asbestos roof shed with mud floor. All the kids received CFBs containing 50 parts P cineraria leaves and 50 parts concentrate mixture. CFB offered to the first group had high protein (183.8 g kg^?1; HP), that offered to the second group had low protein (131.3 g kg^?1; LP) and that offered to the third group had low protein (124.7 g kg^?1) but contained PEG‐6000 (LP‐PEG). The concentrate mixtures in LP and LP‐PEG were without groundnut cake, whereas in LP‐PEG, groundnut cake was replaced by barley and 5 parts PEG‐6000 were incorporated. CFBs were similar in their nutritive value except for crude protein (CP). Prosopis leaves utilized in the CFB contained (g kg^?1 dry matter) 129.1 CP, 535.5 neutral detergent fibre, 395.8 acid detergent fibre and 222.8 acid detergent lignin. There were significant differences in dry matter intake (g day^?1) between HP (1102), LP (1108) and LP‐PEG (1194); the trend in Metabolizable energy intake was similar. During the growth trial, LP kids consumed maximum amount of feed (76.91 kg) followed by HP (75.73 kg) and LP‐PEG (73.12 kg). However, maximum feed efficiency (feed consumed kg^?1 live weight gain) was recorded in LP‐PEG kids (9.59) followed by HP (10.64) and LP (11.60). These differences were statistically significant (p < 0.05). Although there was no significant difference in the digestibility of dry matter among the groups, there was significant difference in the digestibility of CP, neutral detergent fibre and acid detergent fibre. The digestibility of CP was 0.591, 0.484 and 0.645, that of neutral detergent fibre was 0.397, 0.308 and 0.499 and that of acid detergent fibre was 0.168, 0.154 and 0.282 in HP, LP and LP‐PEG, respectively. Rumen metabolites studied 6 h after feeding revealed that there were significant (p < 0.05) differences in the concentrations of ammonia N, tri‐chloro acetic acid precipitable N and total volatile fatty acids among the three groups, but not pH. The rumen enzyme concentrations showed significant (p < 0.05) differences for α‐amylase, whereas the differences were non‐significant for CMcase and protease. After 90 days of feeding trial, the maximum weight gain was recorded in LP‐PEG (7.62 kg) followed by HP (7.23 kg) and LP (6.53 kg). It can be concluded that, when kids are reared under an intensive system on complete feed blocks containing Prosopis leaves, high protein concentrate can be replaced with a low protein concentrate containing 5 parts PEG, which would not only alleviate the negative effects of tannin but would also spare expensive groundnut protein. Copyright © 2005 Society of Chemical Industry