Showing papers by "National Dairy Research Institute published in 2008"

Oral administration of dahi containing probiotic Lactobacillus acidophilus and Lactobacillus casei delayed the progression of streptozotocin-induced diabetes in rats.

Abstract: In this study, the effect of dahi containing probiotic Lactobacillus acidophilus NCDC14 and Lactobacillus casei NCDC19 (73 x 10(8) cfu/g) on progression of streptozotocin (STZ)-induced diabetes in rats (15 g/day/rat) for 28 days was investigated. Feeding of probiotic dahi significantly suppressed the incremental peaks and area under the curve and delayed reduction of insulin secretion during oral glucose tolerance test more than skim milk or control dahi. The feeding of milk products reduced the total cholesterol, triglycerides, LDL and VLDL-cholesterol and increased HDL-cholesterol levels (P<0.05). Moreover, probiotic dahi significantly suppressed STZ-induced oxidative damage in pancreatic tissues by inhibiting the lipid peroxidation and formation of nitric oxide, and preserving antioxidant pool such as glutathione content and activities of superoxide dismutase, catalase and glutathione peroxidase. The results suggest that the supplementation of probiotic Lb. acidophilus and Lb. casei with dahi cultures increased the efficacy of dahi to suppress STZ-induced diabetes in rats by inhibiting depletion of insulin as well as preserving diabetic dyslipidemia, and inhibiting lipid peroxidation and nitrite formation. This may empower antioxidant system of beta-cells and may slow down the reduction of insulin and elevation of blood glucose levels.

Biofunctional Properties of Bioactive Peptides of Milk Origin

Abstract: Milk proteins are currently the main source of a range of biologically active substances which are inactive within the sequence of native protein but can be released by enzymatic hydrolysis. Milk borne bioactive peptides have been found to exhibit various physiological activities such as antihypertensive, opioid, immunomodulatory antimicrobial, antioxidative, antithrombotic, and cytomodulatory. Such bioactive peptides may find use in the treatment of diarrhea, hypertension, thrombosis, dental carries, oxidative stress, mineral malabsorption, and immunodeficiency. These bioactive peptides may be used in formulation of functional foods, nutraceuticals, and natural drugs because of their health benefit effects.

Molecular approaches for identification and characterization of lactic acid bacteria

Abstract: The last few years have produced a revolution in the development of very sensitive, rapid, automated, molecular detection methods for a variety of various species of lactic acid bacteria (LAB) associated with food and dairy products Nowadays many such strains of LAB are considered probiotics The genome-based methods are useful in identifying bacteria as a complementary or alternative tool to phenotypical methods Over the years, identification methodologies using primers that target different sequences, such as the 16S ribosomal RNA (rRNA)-encoding gene, the 16S-23S rRNA intergenic spacer region, the 23S rRNA-encoding, recA and ldhD genes; randomly amplified polymorphic DNA, restriction fragment length polymorphism, denaturing gradient gel electrophoresis, temperature gradient gel electrophoresis, amplification rDNA restriction analysis, restriction enzyme analysis, rRNA, pulse field gel electrophoresis and amplification fragment length polymorphism have played a significant role in probiotic bacteriology Hence, the aim of this review is to provide an overview of some rapid and reliable polymerase chain reaction-based molecular methods used for identifying and differentiating closely related species and strains of LAB associated with food and industry

Functional and safety aspects of enterococci in dairy foods

Abstract: The genus Enterococcus like other LAB has also been featured in dairy industry for decades due to its specific biochemical traits such as lipolysis, proteolysis, and citrate breakdown, hence contributing typical taste and flavor to the dairy foods. Furthermore, the production of bacteriocins by enterococci (enterocins) is well documented. These technological applications have led to propose enterococci as adjunct starters or protective cultures in fermented foods. Moreover, enterococci are nowadays promoted as probiotics, which are claimed for the maintenance of normal intestinal microflora, stimulation of the immune system and improvement of nutritional value of foods. At the same time, enterococci present an emerging pool of opportunistic pathogens for humans as they cause disease, possess agents for antibiotic resistance, and are frequently armed with potential virulence factors. Because of this “dualistic” nature, the use of enterococci remains a debatable issue. However, based on a long history of safe association of particular enterococci with some traditional food fermentations, the use of such strains appears to bear no particular risk for human health. Abundance of knowledge as well as progress in molecular techniques has, however, enabled exact characterization and safety assessment of strains. Therefore, a balanced evaluation of both, beneficial and undesirable nature of enterococci is required. A clear understanding of their status may, therefore, allow their safe use as a starter, or a probiotic strain. The present review describes the broader insight of the benefits and risks of enterococci in dairy foods and their safety assessment.

Hand-made cloned buffalo (Bubalus bubalis) embryos: comparison of different media and culture systems.

Abstract: Hand-made cloning (HMC) has proved to be an efficient alternative to the conventional micromanipulator-based technique in some domestic animal species. This study reports the development of an effective culture system for in vitro culture of zona-free cloned buffalo (Bubalus bubalis) embryos reconstructed using adult skin fibroblast cells as nucleus donor. Cleavage and blastocyst rates observed were 52 and 0% in modified Charles Rosenkrans 2 (mCR2), 61 and 4.6% in modified Synthetic Oviductal Fluid (mSOF), and 82 and 40.3% in Research Vitro Cleave (RVCL; Cook, Australia) medium, respectively. Similarly, higher blastocyst rates (24.5 +/- 4.1%) were observed when zona-free parthenotes were cultured in RVCL medium. Culturing zona-free cloned buffalo embryos on flat surfaces (FS) yielded significantly higher (p < 0.05) blastocyst rates than Well of the Wells (WOW) or microdrops (MD). Furthermore, development in WOW was found to be significantly better than MD culture. The quality of HMC blastocysts was examined using differential staining. This study establishes the application of zona-free nuclear transfer procedures for the production of hand-made cloned buffalo embryos and the development of efficient culture system and appropriate media requirements for enhancing their preimplantation development.

Tannase production by Aspergillus fumigatus MA under solid-state fermentation

Abstract: A tannase yielding fungal culture identified as Aspergillus fumigatus MA was isolated from the effluent collected from a local small scale tannery. The fungal culture produced high yields of extracellular tannase under solid-state fermentation (SSF) using different agro forest residues such as Amla leaves (Phyllanthus emblica), Ber leaves (Zyzyphus mauritiana), Jamun leaves (Syzygium cumini), Jamoa leaves (Syzygium sp.) and Keekar leaves (Acacia nilotica). Among different substrates used, Jamun leaves yielded maximal extra-cellular production of tannase. Various parameters were studied to optimize the extracellular yield of tannase under SSF. The maximum yield of 174.32 U g−1 was obtained at 25°C after 96 h of incubation at pH 5.0. The tap water was used as a moistening agent. A substrate to tap water ratio of 1:1 was found to best for tannase production. Supplementation of the medium with ammonium sulfate as nitrogen source had enhanced tannase production whereas glucose had decreased the enzyme production. This is the first report on production of tannase by Aspergillus fumigatus MA, giving a much higher yield of enzyme under SSF with Jamun leaves as the substrate.

Effect of type of cryoprotectant on morphology and developmental competence of in vitro-matured buffalo (Bubalus bubalis) oocytes subjected to slow freezing or vitrification.

Abstract: The present study examined the effects of different cryoprotectants on morphology and developmental competence of in vitro-matured buffalo oocytes after slow freezing or vitrification. After slow freezing in dimethyl sulfoxide (DMSO), ethylene glycol (EG) or 1,2-propanediol (PROH), at 1.0 or 1.5 m each, the proportion of morphologically normal oocytes recovered was significantly higher (P < 0.05) with 1.5 than 1.0 m for all cryoprotectants and was highest (P < 0.05) for 1.5 m DMSO. Following vitrification, the percentage of morphologically normal oocytes recovered was lower (P < 0.01) for 40% EG than for 40% DMSO, 20% EG + 20% DMSO or 20% EG + 20% PROH. The most common damage, irrespective of the cryopreservation method, was loss of cumulus mass. The cleavage rate and the proportion of vitrified–warmed oocytes that developed to morulae/blastocysts were significantly higher (P < 0.01) for 20% EG + 20% DMSO than for the other groups. A higher proportion of oocytes developed to morulae (11.5% v. 4.3%) or blastocysts (5.4% v. 0.6%) after vitrification in 20% EG + 20% DMSO than after slow freezing in 1.5 m DMSO. In conclusion, vitrification was more effective than slow freezing for the cryopreservation of in vitro-matured buffalo oocytes.

Bovine kappa-casein gene polymorphism and its association with milk production traits

Abstract: Point mutations in exon IV of the bovine κ-casein (CSN3) gene determine two allelic variants, A and B. These variants were distinguished by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis in the indigenous Sahiwal and Tharparkar cattle breeds. DNA samples (252 Sahiwal and 56 Tharparkar) were analyzed for allelic variants of the CSN3 gene. Polymorphism was detected by digestion of PCR-amplified products with HindIII, HhaI and HaeIII restriction enzymes, followed by separation on 3% agarose gels, and resolved by ethidium bromide staining. Allele A of the κ-casein gene occurred at a higher frequency than allele B, in both Sahiwal and Tharparkar breeds. The genotypic frequencies of AA, AB, and BB in the Sahiwal and Tharparkar breeds were 0.758, 0.230 and 0.012, and 0.0.732, 0.250 and 0.018, respectively. The frequencies of alleles A and B in the Sahiwal and Tharparkar breeds were 0.873 and 0.127, and 0.857 and 0.143, respectively. Genotype BB of the kappa-casein gene had more influence on the monthly milk yield, 305-days milk yield, monthly solids-not-fat (SNF) yield, and monthly protein yield, in the Sahiwal cattle.

Changes in skin and rectal temperature in lactating buffaloes provided with showers and wallowing during hot-dry season

Abstract: Twelve Murrah buffaloes in second or third parity during early lactation (50–70 days) were selected from the Institute’s herd. All the buffaloes were kept under loose housing system and were provided ad lib green maize fodder and water to drink during 30 days experiment during the month of August- September. The buffaloes were divided into two groups of six each. Showering group (SG) buffaloes were kept under water showers from 11:00 a.m. to 4:00 p.m., while wallowing group (WG) buffaloes were allowed to wallow in a water pond during the same time. Physiological responses viz. rectal temperature (RT), respiration rate (RR), pulse rate (PR) and skin temperature (ST) were recorded before (8.00 a.m.) and after (4.00 p.m.) showers or wallowing. Skin temperature at different sites i.e. trunk, forehead, udder, udder vein, and neck regions was measured. Skin and rectal temperature of both the groups were non significant in morning but varied (P < 0.01) in the evening. Skin temperature measured at all the sites was significantly lower (P < 0.01) in wallowing buffaloes than the showering group. Further, skin temperature of neck, head, udder, udder vein and RT varied (P < 0.01) in SG and WG buffaloes during periods of study. The significant changes in all the parameters of study further support the evidence on effective cooling of skin by wallowing in comparison to water showers. The correlation data indicated a positive correlation of maximum air temperature with RT in SG but correlation was non-significant in WG. RT was positively correlated with ST in SG (P < 0.05) and WG (P < 0.01). The pooled data analysis of both groups also indicated a positive correlation of maximum temperature with RT (P < 0.05). The morning respiration and pulse rate non-significantly varied in both group, however, in the evening, the respiration rate and pulse rate was more (P < 0.01) in SG in comparison to WG. No adverse effect of wallowing or shower treatment on mastitis incidence and general health of animals was observed.

Dahi containing probiotic Lactobacillus acidophilus and Lactobacillus casei has a protective effect against Salmonella enteritidis infection in mice.

Abstract: Salmonella enteritidis infection has received attention during recent years owing to its high prevalence worldwide. In the present study, the protective effect of probiotic dahi (curd) supplemented with Lactobacillus acidophilus and L. casei against Salmonella enteritidis infection in mice is investigated. Seven days pre-feeding with probiotic dahi significantly increased anti- S. enteritidis sIgA (secretary IgA) antibodies and lymphocyte proliferation in S. enteritidis infected mice. IL-2, IL-6 and IFNγ production were significantly increased in supernatant of cultured splenocytes collected from mice pre-fed with probiotic dahi, while IL-4 levels were not changed significantly. Moreover, activities of β-galactosidase and β-glucuronidase, and counts of S. enteritidis in intestine, liver and spleen were decreased, whereas total lactobacilli in faeces were increased in mice pre-fed with probiotic dahi. Pre-feeding of probiotic dahi for 7 days was more effective than 2 days pre-feeding. Thus, the results indicate that, pre-feeding with probiotic dahi ameliorated S. enteritidis infection by stimulating specific and non-specific immune response. Above all, it lowered colonization of gastrointestinal tract as well as translocation of S. enteritidis.

Cysteamine supplementation of in vitro maturation medium, in vitro culture medium or both media promotes in vitro development of buffalo (Bubalus bubalis) embryos

Abstract: The effects of supplementation of in vitro maturation (IVM) or in vitro culture (IVC) or both IVM and IVC media with cysteamine on the yield, hatching rate (HR) and total cell number (TCN) of buffalo blastocysts were examined. Oocytes obtained from slaughterhouse buffalo ovaries were subjected to IVM and IVF. The IVM or IVC media were supplemented with 0, 50, 100 or 200 µm cysteamine. Supplementation of IVM medium with 50 µm cysteamine increased (P < 0.01) the cleavage rate and blastocyst yield without affecting the HR and TCN whereas a higher concentration of 200 µm significantly (P < 0.05) reduced the blastocyst yield but not TCN. Similar increases in blastocyst yield, without any effect on HR and TCN were observed after supplementation of the IVC medium with 100 (P < 0.01) or 50 µm (P < 0.05) cysteamine, whereas 200 µm cysteamine was ineffective. Supplementation of both IVM medium with 50 µm cysteamine and of IVC medium with 100 µm cysteamine increased the yield of blastocysts and hatched blastocyst by over 100% (P < 0.01) compared with the controls without any adverse effects on HR or TCN. The results of the present study suggest that supplementation of both IVM and IVC media improves the yield of blastocysts without compromising their health.

The effect of probiotic dahi containing Lactobacillus acidophilus and Lactobacillus casei on gastropathic consequences in diabetic rats.

Abstract: In the present study, the effects of oral administration of probiotic dahi containing Lactobacillus acidophilus and Lactobacillus casei on gastropathic consequences in streptozotocin-induced diabetic rats were evaluated, and effects were compared with skim milk- and control dahi-fed groups. The feeding of probiotic dahi did not change the blood glucose levels in chronic hyperglycemic conditions. The rate of charcoal transit was significantly higher in probiotic dahi-fed animals than in those of the diabetic control group (P < .05). Moreover, the oral administration of probiotic dahi significantly increased counts of lactobacilli adherent to epithelial walls and free in the lumen of the small and large intestine, while decreasing attached as well as free coliform counts (P < .05). In addition, probiotic dahi reversed the decrease in total lactobacilli and increase in total coliforms in fecal samples of diabetic animals. It was also shown that oral ingestion of probiotic dahi reduced the oxidative stress marker thiobarbituric acid-reactive species in intestinal tissues and glycosylation of hemoglobin (P < .05). All the effects were predominantly higher in the probiotic dahi-fed group than the skim milk- and control dahi-fed groups. The results indicate that probiotic dahi may be used as a therapeutic regimen to diminish the gastropathic consequences of diabetes.

Use of shatavari (asparagus racemosus) as a galactopoietic and therapeutic herb- a review

Abstract: Asparagus racemosus (Shatavari) is recommended in the Ayurveda for the prevention and treatment of reproductive disorders of women such as sexual debility, ammenorrhea, dysmenorrhea, dysfunctional uterine bleeding, endometriosis, gonorrhea, prolapse of uterus etc. It is also recommended as a galactogogue in case of lactational inadequacy. Asparagus racemosus has been successfully used by some medical practitioners as an anti-inflammatory, anti-microbial and immunomodulator for many infectious diseases. Asparagus racemosus can also improve the milk production and reproduction capacity of dairy animals. The use of Asparagus racemosus can also boost the immune system and consequently prevent the infection of the udder and reproductive organs of cows. It can also be effectively used to reduce the stress of dairy animals and improve their productivity thus producing clean and healthy milk from them.

A method for estimation of urea using ammonia electrode and its applicability to milk samples.

Abstract: A method for the estimation of urea in milk using ammonia electrode is described. Urea is first degraded by urease enzyme into ammonium ion and carbon dioxide at neutral pH. The ammonium ion is then converted into ammonia at alkaline pH. A linear inverse relationship was observed between logarithmic concentration of ammonia or urea and electrode response. Repeatability, expressed as a coefficient of variation, was 1.77% at a level of 8.92 mm-urea in milk. The method was validated in milk samples spiked with between 2 x 10-3 and 10 x 10-3 m-urea and recovery of added urea was quantitative. Whereas, preservative sodium azide at 0.5 g/l or 2 g/l level did not affect results, lower values of urea concentration in presence of Bronopol at 0.5 g/l were observed. Urea levels in milk samples estimated by this method were comparable to standard enzymatic method. The method is simple, fast and is not prone to interference from other milk constituents.

Conjugated linoleic acid producing potential of lactobacilli isolated from the rumen of cattle.

Abstract: Lactobacilli isolated from the rumen of cattle were subjected to morphological and biochemical characterizations followed by PCR-based identification. Among isolates, Lactobacillus brevis was found to be the most prevalent species in the rumen. For in vitro conjugated linoleic acid (CLA) production, the two isolates of L. brevis and one each of Lactobacillus viridescens and Lactobacillus lactis were selected. The sunflower oil (i.e., 0.25, 0.5 and 1.0%; a rich source of linoleic acid) was added to skim milk as a substrate for CLA production by isolates at 37 °C/12 h. L. brevis 02 was found to be the most potential CLA producer (10.53 mg CLA/g fat) at 0.25% concentration of sunflower oil followed by L. brevis 01 (8.27 mg CLA/g fat). However, at higher level of sunflower oil (i.e., 1.0%), L. lactis was the highest CLA producer (9.22 mg/g fat) when compared to L. brevis and L. viridescens. The results indicated that L. brevis and/or CLA production was inhibited with increasing concentration of sunflower oil in skim milk. In contrast, L. lactis and L. viridescens could tolerate the increasing concentrations of sunflower oil and produced higher CLA. Overall, L. brevis extends a possibility to be used as a direct-fed microbial for ruminants to increase the CLA content in milk, however, in vivo trials are needed for validation of results obtained.

Barriers and Facilitators to Undergoing Hepatitis C Virus (HCV) Testing through Drug Treatment Programs

Abstract: Given the high prevalence of hepatitis C virus (HCV) infection among drug users, HCV testing is critical in this population. While many drug treatment programs offer HCV testing, patients often do not utilize this essential program-facilitated service. Summarizing data collected in semi-structured interviews and surveys with patients in 25 programs, this paper identifies barriers and facilitators to being tested for HCV through the program. Barriers include the patient's belief that she/he is not HCV infected, fear of needles, fear of obtaining a positive HCV test result, fear of disclosure of such a result, and fear of inappropriate or disrespectful treatment during the testing process. In addition, 38% of HCV sero-unaware or sero-negative patients completing the survey did not know that HCV testing was offered through their programs. Salient facilitators for those tested through their programs include support from staff in explaining the importance of testing and help in understanding and coping with te...

An update on reproduction in yak and mithun.

Abstract: Yak and mithun are two domesticated herbivores of high economic importance to the farming community living in highlands. Improved yak and mithun production could significantly enhance the living standards of these highlanders. Over the years, their dwindling numbers have been a cause of serious concern. In view of the lack of knowledge on the reproductive physiology of these ruminants, studies have been undertaken to investigate their reproductive endocrinology in recent years. This paper attempts to present the latest information on the endocrine changes associated with their various reproductive processes viz. growth and puberty, oestrous cyclicity and oestrous behaviour, ovulation, and, pregnancy and parturition. The paper also provides the recent developments on research done towards the enhancement of yak and mithun reproductive efficiencies through endocrine and embryo biotechniques.

Effect of Modified Atmosphere Packaging (MAP) and Storage on the Chemical Quality of Paneer

Abstract: Traditional food packaging protects food from external contamination, oxygen, water vapour and light. However, newer packaging technologies such as Modified Atmosphere Packaging (MAP) do more than just provide protection from outside influences. The study was conducted to increase the shelf life of paneer by using MAP technique. The paneer samples were packaged in high barrier bags (LLD/BA/Nylon-6/BA/LDPE) under different atmospheres: atmospheric air (atm1), vacuum (atm2), 100% CO2 (atm3) and 100% N2 (atm4). A headspace to product ratio of 1-2 litres gas / kg product was initially set in the MAP system and stored the samples at 7±1oC. Periodically, paneer samples were evaluated for changes in chemical characteristics. The analysis of variance of the data revealed that the MAP had significant influence on moisture, titratable acidity, pH, free fatty acids, and tyrosine content of the paneer samples during storage.

Stimulation of innate immunity by oral administration of dahi containing probiotic Lactobacillus casei in mice.

Abstract: Immunomodulatory effects of a dahi (strained yogurt) containing probiotic Lactobacillus casei, designated "probiotic dahi," was evaluated in Swiss albino mice during 8 days of feeding and compared with control dahi-, nonfermented milk-, and no milk product diet-fed (control) groups. Lysosomal enzymes (beta-galactosidase and beta-glucuronidase) and phagocytic activities were estimated in peritoneal macrophages of animals fed with different experimental diets on days 2, 5, and 8. The oral administration of probiotic dahi increased (by 84%) beta-galactosidase activity in supernatant of cultured macrophages and achieved the highest values on day 2 and thereafter decreased up to day 8, at which no effect on beta-glucuronidase activities was observed; it was the same as the control group. Moreover, phagocytic activity also increased in probiotic dahi-fed mice after days 2 and 5 and then decreased after 8 days, but was still higher than in nonfermented milk and control dahi-fed groups. The counts of total lactobacilli significantly increased after feeding of probiotic dahi as compared to the other groups. However, no significant changes were observed in beta-galactosidase and beta-glucuronidase activities and phagocytic activity of peritoneal macrophages isolated from nonfermented milk- and normal diet-fed groups. The results of the present study reveal that nonspecific immune response markers were stimulated in mice by feeding of probiotic dahi containing probiotic L. casei instead of milk alone and that the effect was greater than in control dahi.