Prabhu Balan

Evaluation of combined effects of ageing period and freezing rate on quality attributes of beef loins

The objective of our study was to evaluate the combined effects of ageing period and different freezing rates on meat quality attributes of beef loins. Pairs of loins (M. longissimus at 1 day post mortem) from 12 carcasses were divided into four equal portions and randomly assigned to four ageing/freezing treatments (aged only, frozen only, and 3 or 4 weeks ageing at -1.5°C then frozen). Two freezing methods (fast freezing by calcium chloride immersion or slow freezing by air freezer at -18°C) were applied to the loin sections. Fast freezing had no effect on shear force (P>0.05), but significantly improved the water-holding capacity of the aged/frozen loins by reducing purge and drip losses. Ageing-then-freezing significantly improved shear force values of loins compared to both the aged only and frozen only loins. These observations suggest that fast freezing will add more value to the aged/frozen/thawed meat by minimising the amount of water-loss due to the freezing/thawing process.

Orally Administered Ovine Serum Immunoglobulins Influence Growth Performance, Organ Weights, and Gut Morphology in Growing Rats

In this study, our aim was to determine whether orally administered ovine serum Ig improved growth performance, organ weights, and gut morphology in growing rats and whether the method of manufacture of ovine serum Ig affected its bioactivity. Ninety Sprague-Dawley male rats were used in a 21-d growth study and were fed a basal control diet (BD; no Ig) and 5 test diets: spray-dried porcine plasma (SDPP), freeze-dried ovine Ig (FDOI), 2 concentrations of spray-dried ovine Ig (SDOI(100) and SDOI(150)), and inactivated ovine Ig (IOI). Diets were isocaloric and contained the same amount of the first limiting amino acids, methionine plus cysteine. The body weight gain:feed ratio was higher (P < 0.05) for the FDOI-fed rats than for the BD- and IOI-fed groups. FDOI rats had higher jejunum (P < 0.05) and colon weights (P < 0.05) at the end of the study than rats in the BD group. Compared with the SDOI(100)-fed group, the FDOI group supported higher (P < 0.05) duodenum and colon weights. For gut morphology, the FDOI and the BD and IOI groups differed (P < 0.05). The FDOI-fed rats had longer (P < 0.05) villi and greater villi surface areas in the duodenum, jejunum, and ileum than the rats fed SDOI(100). An ovine Ig fraction selectively improved growth performance, organ weight, and gut morphology in growing rats. Compared with spray-drying, a freeze-drying procedure appears to preserve a higher degree of immunological activity.

Small heat shock protein degradation could be an indicator of the extent of myofibrillar protein degradation.

The objective of the present study was to evaluate the relationship between small heat shock proteins (sHSP) degradation and tenderness development of beef loins at different ultimate pH (pHu). A total of twelve loins (M. longissimus dorsi) from steers were obtained at 1 day post mortem. Shear force and proteolysis of each loin were analyzed at 1 and 28 days post mortem. The loins at intermediate pHu (5.8 to 6.0) showed more variation in tenderness compared to the loins at low pHu (<5.8), where few samples were still tough (>10kgF) at 28days. The intact sHSP20 was more pronounced (P<0.05) in the intermediate pHu loin compared to the low pHu counterpart. Further, high correlations between the degradation of both sHSP and myofibrillar proteins were observed (e.g. r=0.94; degraded sHSP27 and degraded desmin). The result of this study suggests that the extent of sHSP degradation could be an indicator of myofibrillar protein degradation and tenderness.

Ovine Serum Immunoglobulin Has Immunomodulatory Effects in Growing Rats Gavaged with Salmonella enteritidis

In this study, we aimed to determine whether orally administered ovine serum Ig modulate aspects of immunity and associated gut microflora in growing rats challenged with Salmonella enteritidis. The 4 groups consisted of rats fed a casein-based control diet (BD; ungavaged) and 3 groups of rats gavaged with 1 × 10(7) viable Salmonella enteritidis and fed a BD diet, a BD diet containing freeze-dried ovine Ig (FDOI), or a BD diet containing inactivated ovine Ig (IOI). The rats were randomly allocated to 1 of the 4 diets (n = 15) and consumed it for 18 d. They were orally gavaged on d 15. Phagocytic activity of peripheral blood leukocyte and lymphocyte proliferation in the presence of the concanavalin A (ConA) were greater (P < 0.05) in the ungavaged BD- and gavaged FDOI-fed rats than in the gavaged rats fed either the BD or IOI diet. ConA-stimulated Peyers patch cells and splenocytes from the gavaged rats fed the FDOI diet produced more IFNγ, IgA, and IgG than the gavaged rats fed either the BD or IOI diet (P < 0.05). The gavaged FDOI-fed rats had higher ileal and colonic digesta and plasma concentrations of anti-Salmonella secretory sIgA and secretory sIgG (P < 0.05). DNA analysis of a denatured gradient gel electrophoresis profile revealed that 6 of 10 bands had sequence similarity to probiotic strains of bacteria in the ileum and colon of the gavaged FDOI-fed rats. In conclusion, an ovine Ig fraction modulated various indices of immune function and associated gut microflora in growing rats inoculated with Salmonella.

Dietary supplementation with ovine serum immunoglobulin is associated with an increased gut luminal mucin concentration in the growing rat

The mucus layer covering the gut epithelium is pivotal to host defence and is affected by various dietary components. Part of the reported beneficial effect of dietary immunoglobulins (Igs) on gut health may be due to effects on the gut mucus layer. The aim was to determine whether orally administered ovine serum Ig influence goblet cell count, mucin gene expression and digesta mucin protein content in the gut of the growing rat. Fourteen Sprague-Dawley male growing rats were used in a 21-day study and were fed either a casein-based control diet (CON; no Ig) or a similar diet but containing freeze-dried ovine Ig (FDOI). Daily food intake and growth rate were not affected by the dietary treatments. When compared to the rats consuming CON diet, those consuming the FDOI diet had significantly (P < 0.05) more intact and cavitated goblet cells in the intestinal villi. A similar result was found for crypt goblet cells in the small intestine and colon. Ileal Muc2, Muc3, Muc4 and stomach Muc5Ac mRNA expressions for the FDOI animals were higher (P < 0.05) compared to the the CON animals. Mucin protein content was higher (P < 0.05) in the stomach, ileum and colonic digesta of rats fed the FDOI diet. In conclusion, orally administered FDOI influenced gut mucins in the growing rat as evidenced by increased mucin gene expression and digesta mucin protein concentrations as well as an increased goblet cell count.

Kiwifruit, mucins, and the gut barrier.

Kiwifruit has long been regarded in China, where it originated from, for its health properties and particularly in relation to digestion and general gut health. There are a number of physical and chemical properties of the fruit, including its dietary fiber content, the presence of raphides, its high water holding capacity and actinidin content, that suggest that kiwifruit may be effective in influencing gut mucin production and thus enhancing the integrity of the gut barrier. The mucous layer, which comprises mucins and other materials, overlying the mucosal epithelium, is an important component of the gut barrier. The gut barrier plays a crucial role in separating the host from the often noxious external environment. The mucous layer, which covers the entire gastrointestinal tract (GIT), is the front line of innate host defense. There have been few direct studies of the effect of kiwifruit ingestion on mucin production in the GIT, and findings that are available using animal models are somewhat inconsistent. Taking results for digesta mucin content, number of goblet cells, and mucin gene expression, together, it would seem that green kiwifruit and possibly gold kiwifruit do influence gut mucin production, and the kiwifruit as part of a balanced diet may help to maintain the mucous layer and gut barrier. More corroborative experimental evidence is needed, and studies need to be undertaken in humans.

Dietary supplementation with ovine serum immunoglobulin attenuates acute effects on growth, organ weights, gut morphology and intestinal mucin production in the growing rat challenged with Salmonella enteritidis.

The aim was to determine the effect of orally administered ovine serum immunoglobulin (Ig) on growth performance, organ weight, gut morphology and mucin production in the Salmonella enteritidis--gavaged growing rat. Four groups consisted of non-gavaged rats fed a casein-based control basal diet (BD) and three groups of rats gavaged with 1×10(7) CFU S. enteritidis and fed a casein-based diet, a diet containing freeze-dried ovine Ig (FDOI) or a casein-based diet containing inactivated ovine Ig (IOI). The rats were randomly allocated to one of the four groups (n=15/group) and received their respective diets for an 18-day experimental study. Gavaging took place on day 15. Average daily gain and body gain : feed ratio (post-gavage, 3 days) were significantly (P<0.05) higher for the Salmonella-challenged rats fed the FDOI diet compared to those fed the BD and IOI diets. At the end of the study, the small intestine and colon were significantly (P<0.05) heavier for the gavaged rats fed the FDOI diet compared to the gavaged rats fed either the BD or IOI diet. Moreover, the relative weights of the caecum, liver and spleen of the gavaged rats fed the BD or IOI diet were significantly (P<0.05) heavier compared to the gavaged rats fed the FDOI diet. Generally, the gavaged rats fed the FDOI diet had significantly (P<0.05) higher goblet cell counts and luminal mucin protein contents than the gavaged rats fed either the BD or IOI diet and had a more functional gut morphology. Overall, the FDOI fraction prevented the acute effects of S. enteritidis.

Recovery of intact IgG in the gastrointestinal tract of the growing rat following ingestion of an ovine serum immunoglobulin.

The aim of this study was to determine whether orally ingested ovine serum IgG partly resists digestion in the growing rat. Fifteen Sprague-Dawley male rats were allocated to one of three diets for a 3-week study: a control diet (CON) and two test diets containing either freeze-dried ovine serum immunoglobulin (FDOI) or inactivated ovine serum immunoglobulin (IOI). Samples of stomach chyme and intestinal digesta from the ad libitum-fed rats were subjected to ELISA and Western blot analysis. Amounts of intact ovine IgG for the FDOI diet were found to be 13.9, 20.0, 34.1, 13.0 and 36.9 μg in the total wet digesta from the stomach chyme, duodenal, jejunal, ileal and colonic digesta respectively. Qualitative detection by Western blot revealed the presence of intact ovine serum IgG with a ~150 kDa MW. This was detected in all of the gut segments (stomach chyme, duodenal, jejunal, ileal and colonic digesta) for growing rats fed the FDOI diet. No ovine IgG was detected in the chyme or digesta from rats fed the CON or the IOI diets. Ovine serum IgG partly resisted digestion in the growing rat fed the FDOI diet and was found throughout the digestive tract. These results provide a basis to explain the reported biological effects of orally administered immunoglobulin.

Orally administered ovine serum immunoglobulins modulate the intestinal levels of Lactobacillus and enterobacteria in the growing rat

The aim was to determine whether orally administered ovine serum immunoglobulins modulate the gut microbiota in the growing rat. Thirty Sprague-Dawley male rats were used in a 21-d study and fed either a basal control diet (control; no immunoglobulin) or a similar diet containing freeze-dried ovine immunoglobulin (ovine Ig) with 15 individually fed rats per diet. Bacterial DNA isolated from ileal and colonic digesta were subjected to PCR-denaturing gradient gel electrophoresis (PCR-DGGE). In the ileum, the DGGE band number and diversity index were greater (P < 0.05) for rats fed the ovine Ig than those fed the control diet. The DNA sequencing of a selected DGGE band in the ovine Ig-fed rats revealed 99% similarity to the Lactobacillus strains. The quantitative PCR data revealed that supplementation of the diet with the ovine Ig fraction supported the growth of Lactobacillus and conversely decreased the number of enterobacteria in ileal and colonic digesta. Inclusion of the ovine Ig fraction led to a greater (P < 0.05) ratio for total Lactobacillus to total bacteria and total Lactobacillus to enterobacteria. The results from the present study show that dietary supplementation with ovine Ig may alter the intestinal environment by a specific enrichment of Lactobacillus strains and depletion of enterobacteria.

Intact but not denatured ovine serum immunoglobulins positively modulate mucosal immune mediators in the growing rat challenged with Salmonella enteritidis

Immunoglobulins are major glycoproteins that modulate the immune response of gut-associated lymphoid tissue. In the present study, we sought to determine whether orally administered ovine serum immunoglobulins modulate selected indices of mucosal immune function and immune mediators in the growing rat challenged with Salmonella enteritidis. Rats were fed a casein-based basal control diet (BD; unchallenged). Three groups of rats were challenged orally with 1 x 10(7) viable S. enteritidis on day 15 of the study and were fed the BD, the BD containing freeze-dried ovine immunoglobulins (FDOI), or the BD containing autoclaved ovine immunoglobulins (AOI; negative control diet). The rats were randomly allocated to one of the four groups (n 15) and consumed their diet for 18 d. In all of the intestinal segments, the challenged rats fed either the BD or AOI diet produced higher (P<0·05) mucosal levels of interferon-g, TNFa, IgA and myeloperoxidase activity than the challenged rats fed the FDOI diet. In contrast, IL-4 and IL-10 levels were higher in the challenged FDOI-fed rats compared with the other challenged groups. The challenged FDOI-fed rats had higher (P<0·05) mucosal anti-Salmonella IgA and IgG in all of the intestinal segments except the jejunum and ileum. Generally, the challenged rats receiving the FDOI diet had significantly (P<0·05) higher mucosal mucin protein content compared with challenged rats receiving either the BD or AOI diet. In conclusion, an ovine immunoglobulin fraction positively modulated some selected indices of mucosal immune function and its mediators in growing rats challenged with S. enteritidis.