Bovine colostrum promoted ileal health in newborn lambs at 24 h after birth: insight from intestinal morphology and innate immunity.

The contribution of colostrum to passive immunity transfer and intestinal protection in newborn ruminants is well known; however, it is currently unclear how colostrum intake affects intestinal innate immunity. We investigated the effects of bovine colostrum intake on ileal morphology, expression of genes involved in intestinal innate immunity, and serum concentrations of inflammatory cytokines in newborn lambs. Twenty-seven newborn male Hu lambs were used, of which 18 were bottle-fed either bovine colostrum (C24h; n = 9) or bovine mature milk (M24h; n = 9) within the first 2 h after birth at an intake of approximately 8% of BW; the remaining nine lambs did not receive any feeding (N24h). Blood and ileal tissue samples were collected after the lambs were slaughtered at 24 h after birth. Ileal villus height and villus height-to-crypt depth ratio were significantly higher in C24h than those in N24h and M24h lambs (P < 0.01). Messenger RNA (mRNA) abundance of toll-like receptor (TLR)-2, TLR3, TLR4, TLR6, TLR7, TLR8 and tumour necrosis factor alpha in the ileum was lower in C24h than that in N24h lambs (P < 0.05). Moreover, C24h lambs had a lower TLR3 mRNA abundance (P < 0.01) and a trend of lower TLR6 (P = 0.06) and interleukin 1 beta (P = 0.08) expression compared with those in M24h lambs. We also observed strong positive correlations of tumour necrosis factor alpha expression with that of TLR2 (r = 0.71; P < 0.001), TLR4 (r = 0.88; P < 0.001) and TLR8 (r = 0.83; P < 0.001). Interestingly, the expression of barrier-related molecules, including mucin-13, lysozyme, claudin (CLDN)-1, CLDN2, CLDN4, CLDN7, CLDN12, occludin, zonula occluden-1 and junctional adhesion molecule-1, was consistently lower in C24h lambs than that in N24h and M24h lambs (P < 0.05). These results indicated that the beneficial roles of colostrum intake on intestinal protection in newborn lambs were associated with low TLR expression, which was reflected by improved intestinal development and reduced inflammatory response. Further studies using fluorescence in situ hybridisation and immunohistochemical methods are needed to further explore the mechanisms underlying the lower expression of intestinal barrier-related molecules due to colostrum feeding.

Dose and time response of ruminally infused algae on rumen fermentation characteristics, biohydrogenation and Butyrivibrio group bacteria in goats.

BACKGROUND: Micro-algae could inhibit the complete rumen BH of dietary 18-carbon unsaturated fatty acid (UFAs). This study aimed to examine dose and time responses of algae supplementation on rumen fermentation, biohydrogenation and Butyrivibrio group bacteria in goats. METHODS: Six goats were used in a repeated 3 × 3 Latin square design, and offered a fixed diet. Algae were infused through rumen cannule with 0 (Control), 6.1 (L-Alg), or 18.3 g (H-Alg) per day. Rumen contents were sampled on d 0, 3, 7, 14 and 20. RESULTS: H-Alg reduced total volatile fatty acid concentration and acetate molar proportion (P < 0.05), and increased propionate molar proportion (P < 0.05), whereas L-Alg had no effect on rumen fermentation. Changes in proportions of acetate and propionate in H-Alg were obvious from d 7 onwards and reached the largest differences with the control on d 14. Algae induced a dose-dependent decrease in 18:0 and increased trans-18:1 in the ruminal content (P < 0.05). H-Alg increased the concentrations of t9, t11-18:2 and t11, c15-18:2 (P < 0.05). L-Alg only seemed to induce a transient change in 18-carbon isomers, while H-Alg induced a rapid elevation, already obvious on d 3, concentrations of these fatty acid rose in some cases again on d 20. Algae had no effect on the abundances of Butyrivibrio spp. and Butyrivibrio proteoclasticus (P > 0.10), while H-Alg reduced the total bacteria abundance (P < 0.05). However, this was induced by a significant difference between control and H-Alg on d 14 (-4.43 %). Afterwards, both treatments did not differ as increased variation in the H-Alg repetitions, with in some cases a return of the bacterial abundance to the basal level (d 0). CONCLUSIONS: Changes in rumen fermentation and 18-carbon UFAs metabolism in response to algae were related to the supplementation level, but there was no evidence of shift in ruminal biohydrogenation pathways towards t10-18:1. L-Alg mainly induced a transient effect on rumen biohydrogenation of 18-carbon UFAs, while H-Alg showed an acute inhibition and these effects were not associated with the known hydrogenating bacteria.

Effects of garlic oil on milk fatty acid profile and lipogenesis-related gene expression in mammary gland of dairy goats.

BACKGROUND: Garlic oil (GO) has blood lipid-lowering effects. Milk fatty acid (FA) originates partly from plasma, and can be affected by the mammary lipogenesis. This study aimed to investigate GO effects on milk FA profile and mammary lipogenesis-related gene expression. Early-lactation goats were randomly allocated to four treatments with six goats each, and offered corn silage ad libitum and fixed amount of 0.79 kg day(-1) dry matter (DM) concentrate mixed with GO (0, 0.57, 1.14, 1.71 g kg(-1) DM) for 30 days consisting of 26-day adaptation. RESULTS: Intake of corn silage reduced (P≤0.05) as GO level increased in the concentrate. Lipase activity and lactose content linearly increased, while non-esterified FA concentration quadratically decreased with increasing GO level (P≤0.05). The proportions of short- and medium-chain (C14:0, C15:0 and C16:0) and saturated FA decreased, whereas C18, cis9 trans11 conjugated linoleic acid (c9t11 CLA), t10c12 CLA, monounsaturated and polyunsaturated FA, and some ≥ C20 FA proportions increased in a linear manner with increasing GO level (P≤0.05). The mRNA abundance of genes remained unchanged (P > 0.1) as GO level increased. CONCLUSION: Garlic oil altered milk FA profile and these effects may not be related to the mammary lipogenesis-related genes expression.

Bacterial adhesion to silica sand as related to Gibbs energy variations.

Bacterial adhesion to silica sand was related to variations in system Gibbs energy DeltaG(adh). Two typical Gram-positive bacterial strains of Streptococcus mitis and Lactobacillus casei were used as the model bacteria in this research. Impacts of solution chemistry and goethite coating of silica sand on bacterial adhesion were also explored. S. mitis and L. casei had negative DeltaG(adh) with both uncoated and goethite-coated silica sand, demonstrating their adhesion potentials to these substrate. After goethite coating, DeltaG(adh) decreased (negatively increased) for both S. mitis and L. casei. In the presence of rhamnolipid biosurfactant, DeltaG(adh) increased (negatively decreased) in answer to the increase of the rhamnolipid biosurfactant concentration. Bacterial percentage adhesion to silica sand corresponded to DeltaG(adh). This study demonstrated that bacterial adhesion to substrate could be explained in terms of bacterial, substratum and intervening medium physicochemical surface properties, which can be independently determined based on contact angle measurements.

lux-marked Pseudomonas aeruginosa lipopolysaccharide production in the presence of rhamnolipid.

Rhamnolipid produced by Pseudomonas aeruginosa during the late logarithmic growth phase has been reported to be an effective biosurfactant. In the presence of rhamnolipid, P. aeruginosa had a higher specific lipopolysaccharide production, which was attributed to the increase of carbon to nitrogen ratios owing to the increase of the solubility of hydrophobic hydrocarbons, favoring the synthesis of lipopolysaccharides. P. aeruginosa also had a higher ratio of lipopolysaccharides in the growth medium to those on cell surfaces than in the absence of rhamnolipid because the presence of rhamnolipid stimulated the release of lipopolysaccharides from P. aeruginosa cell outer membranes. The release of lipopolysaccharides from cell surfaces made P. aeruginosa exhibit a more hydrophobic surface, enhancing the accumulation of hydrophobic hydrocarbons on P. aeruginosa cell surfaces and consequently resulting in a higher growth rate.

Bacterial desorption in water-saturated porous media in the presence of rhamnolipid biosurfactant.

We investigated the effects of transients in elution chemistry on bacterial desorption in water-saturated porous media. Two typical Gram-positive bacterial strains of Lactobacillus casei and Streptococcus mitis were used as the model bacteria in this research. These two strains were first deposited in the porous medium, after which the medium with deposited bacteria was flushed with rhamnolipid biosurfactant solutions with a step increase in concentrations, and pulse-type bacterial releases were obtained. Bacterial desorption was quantified from bacterial breakthrough curves. It was found that bacterial retention in silica sand corresponded to bacterial interaction free energies with silica sand evaluated at the equilibrium distance, which were calculated based on independently determined bacterial, sediment and solution surface thermodynamic properties. With the increase in rhamnolipid biosurfactant concentrations, interactions between bacteria and silica sand decreased, and consequently less bacteria were retained. The decrease in interactions between bacteria and silica sand with increasing rhamnolipid biosurfactant concentrations was attributed to a decrease in the solution electron acceptor parameter of the Lewis acid/base component of surface tension, gamma3+. The increase in rhamnolipid biosurfactant concentrations favored the decrease in solution gamma3+, and consequently decreased the interactions between bacteria and silica sand.

Bacterial deposition in porous medium as impacted by solution chemistry.

Bacterial transport in porous medium was investigated by means of column experiments using typical rod-shaped bacteria of Escherichia coli and Pseudomonas fluorescens. Mobility of E. coli and P. fluorescens in silica gel decreased with increasing ionic strength of the solution. In the presence of nonionic surfactants, the mobility of E. coli and P. fluorescens increased, and this was more pronounced at lower than at higher ionic strength. Bacterial transport in the porous medium was described by the equilibrium-kinetic two-region model and bacterial deposition was assumed to occur in the kinetic adsorption region only. Quantified bacterial deposition from bacterial column breakthrough curves was related to electrostatic and Lifshitz-van der Waals interactions between bacterial cells and medium surfaces. It was found that electrostatic interactions played a more important role than Lifshitz-van der Waals interactions in determining bacterial deposition in the porous medium, and were actually the barrier for bacteria to attach to the porous medium.

Impact of lipopolysaccharide coating on clay particle wettability.

Impact of lipopolysaccharide coating on kaolinite and Na-montmorillonite wettability was investigated. Kaolinite had greater diiodomethane contact angles, smaller water and formamide contact angles than Na-montmorillonite. After lipopolysaccharide coating, diiodomethane and formamide contact angles decreased, while water contact angles increased for both kaolinite and Na-montmorillonite. The decrease and increase in liquid contact angles after lipopolysaccharide coating were most pronounced for lipopolysaccharide extracted from Pseudomonas aeruginosa, followed by Pseudomonas fluorescens and Echerichia coli. Clay particle wettability was determined by particle surface thermodynamic properties. Both kaolinite and Na-montmorillonite exhibited a monopolar surface and the monopolarity decreased after lipopolysaccharide coating, indicating an increase in hydration or surface wetness. The origins of interactions of clay particles with water molecules were discussed and related to clay particle water wettability.

Soil microbial activities and carbon and nitrogen fixation.

Soil microbial activity that reflects microbiological processes of soil microorganisms is the potential indicator of soil quality, as plants rely on soil microorganisms to mineralize organic nutrients for growth and development. Soil microorganisms also process plant litter and residues into soil organic matter, a direct and stable reservoir of carbon and nitrogen that consists of living and dead organic materials subject to rapid biological decomposition. In natural systems, the action of soil microorganisms is a major determinant of efficient nutrient cycling. This paper reviews the current state of knowledge on the fate of soil microorganisms in terms of carbon and nitrogen fixation.