LP Supplementation Research Articles

Beneficial effects of Lactobacillus plantarum on growth performance, immune status, antioxidant function and intestinal microbiota in broilers

Lactobacillus plantarum (L. plantarum) has been globally regarded as antibiotic alternative in animal farming in the past few years. However, the potential function of L. plantarum in broilers has not been systemically explored. In this study, a total of 560 one-day-old yellow-feathered broilers were randomly divided into 3 groups, fed with basal diet and drank with L. plantarum HJZW08 (LP) at the concentration of 0 (CON), 1000 × 10^5 (LP1000), and 2000 × 10^5 CFU/L (LP2000) for 70 d. Results showed that the body weight (BW), average daily gain (ADG), average daily feed intake (ADFI), immunoglobulin A (IgA), IgY, and anti-inflammatory interleukin 10 (IL-10) were markedly improved (P < 0.05), while the levels of pro-inflammatory IL-2, IL-1β, IL-6, and tumor necrosis factor-α (TNF-α) in serum were decreased (P < 0.05) in the LP2000 group comparing with the CON group. Besides, LP treatment groups prominently increased the levels and activities of antioxidant enzymes and decreased the content of malondialdehyde (MDA). Additionally, the levels of isobutyric acid in the LP1000 and LP2000 groups and isovaleric acid in the LP2000 group were significantly improved. More importantly, the α-diversity and microbial structure of intestinal microbiota were pronounced altered by LP supplementation. The results showed that only the relative abundance of Actinobacteriota was significantly increased in the LP2000 group, while 6 kinds of bacteria on genus level were significantly changed. For further validation, linear discriminant analysis with effect size (LEfSe) plots revealed that 8 amplicon sequence variants (ASVs) were predominant in the CON group, while Bacteroides and other beneficial species such as Lactimicrobium massiliense (ASV4 and ASV36), Intestinimonas butyriciproducens (ASV71), and Barnesiella viscericola (ASV152 and ASV571) were enriched in the LP groups. Taken together, dietary supplementation with LP obviously enhanced the immune status, antioxidant capacity, and stabilized the cecal microbiota and SCFAs, contributing to the improvement of growth performance of broilers. Our study laid good foundation for the application of probiotic Lactobacillus in animal industry in the future.

Lactobacillus plantarum Decreased Ammonia Emissions through Modulating Cecal Microbiotain Broilers Challenged with Ammonia.

Probiotic supplementation has become a prominent method of decreasing ammonia emissions in poultry production. The present study was conducted to investigate the influence of Lactobacillus plantarum on ammonia emission, immune responses, antioxidant capacity, cecal microflora and short chain fatty acids, and serum metabolites in broilers challenged with ammonia. A total of 360 1-day-old yellow-feathered broilers were randomly divided into three treatment groups: birds fed with a basal diet (CON), a basal diet supplemented with ammonia (AN), and a basal diet supplemented with 2.5 × 108 CFU L. plantarum kg-1 and challenged with ammonia (LP). Data showed that L. plantarum supplementation decreased ammonia more than 30% from day 48, and significantly reduced the levels of serum urea nitrogen and ammonia, fecal urease, and ammonium nitrogen compared with those on CON. Compared with AN and CON treatments, LP administration increased (p < 0.05) the concentration of serum immunoglobulin Y (IgY), IgM, and IL-10, as well as the serum total-antioxidant capacity (T-AOC) and GSH-Px, and decreased (p < 0.05) IL-1β, IL-6, and TNF-α. Furthermore, birds supplemented with LP had higher (p < 0.05) cecal contents of short chain fatty acids (SCFAs) than AN birds and had more butyrate than CON birds. Data from 16s high throughput sequencing showed that LP supplementation significantly increased (p < 0.05) the Shannon and Simpson indices of bird cecal microflora, and Alloprevotella dominated the LP birds. The function prediction of cecal microflora indicated that LP treatment significantly increased alanine aspartate and glutamate metabolism, starch and sucrose metabolism, exosome, mismatch repair, homologous recombination, DNA repair and recombination proteins, and amino acid-related enzymes. The serum metabolome showed that LP supplementation significantly changed the aminoacyl-tRNA, pantothenate and acetyl-coenzyme A, arginine, phenylalanine, tyrosine and tryptophan, valine, leucine, and isoleucine biosynthesis; purine, beta-alanine, galactose, histidine, alanine, aspartate and glutamate, glyoxylate and dicarboxylate, pyruvate and thiamine metabolism, melanogenesis, and citrate cycle.

Lactobacillus plantarum supplementation alleviates liver and intestinal injury in parenteral nutrition-fed piglets.

Long-term parenteral nutrition (PN) causes PN-associated liver disease, for which therapeutic approaches are limited. This study aimed to investigate the effects of Lactobacillus plantarum CGMCC 1258 (LP) on liver and intestinal injury in PN-fed neonatal piglets. The piglets received PN with or without oral LP for 14 days. The levels of liver enzymes and inflammatory markers were measured using biochemical kits and quantitative real-time polymerase chain reaction. Serum fibroblast growth factor 19 (FGF19) was detected using an enzyme-linked immunosorbent assay. The bile acid (BA) profiles in the liver, serum, and intestinal contents were determined using ultraperformance liquid chromatography coupled with mass spectrometry. The composition of intestinal bacteria was analyzed with 16S rRNA gene amplicon sequencing. LP supplementation was associated with improved markers of liver disease, inflammation, and oxidative stress in PN-fed piglets. Moreover, markers of intestinal injury and inflammation were alleviated by LP in PN-fed piglets. Mechanistically, LP increased the abundance of Lactobacillus in ileal contents and stimulated FGF19 expression in ileal mucosa. Subsequently, it increased the expression of small heterodimer partner (SHP) and inhibited cholesterol 7α-hydroxylase (CYP7A1) expression in the liver. Additionally, LP altered the systemic composition and metabolism of BAs. LP alleviated liver and intestinal injury in PN-fed neonatal piglets by altering the composition of intestinal bacteria and BAs.

A study about the application of probiotics on Apis mellifera

Our study aimed to evaluate the effects of applying the common animal probiotics Lactobacillus plantarum strain JCM 1149 (LP), Bacillus subtilis subsp subtilis strain 168 (BS), Bifidobacterium adolescentis ATCC 15703 (BA), and Clostridium butyricum strain VP13266 (CB) in beekeeping systems. In a laboratory-controlled trial, the effects of LP, BS, BA and CB on nutrient deposition and immune properties of honey bees were evaluated. LP, BA, and CB enhanced pepsin activity, BS and LP increased lipase activity, and LP increased sucrase activity in the midgut, suggesting that these probiotics can improve the utilization of nutrients in honey bees by improving the activity of digestive enzyme activity. Besides, CB improved the total antioxidant capacity (T-AOC) and the activity of superoxide dismutase (SOD) and catalase. LP and BS increased T-AOC and SOD activity. BS up-regulated the expression of Abaecin, Apidaecin, and Defensin-1. LP up-regulated the expression of Defensin-2. BA and CB up-regulated the expression of Abaecin and Apidaecin, respectively. According to the results of the laboratory-controlled trial, LP and BS could be more beneficial for honey bees compared to the other two tested strains. To study the effect of LP and BS supplementation in the field, we evaluated the colony size, the weight of newly emerged workers, the content of short-chain fatty acids, and the composition of the gut bacterial community. BS increased the population size of the colonies, the weight of newly emerged workers, and the relative abundance of Lactobacillus, showing it to be a beneficial symbiont. BS also significantly increased the content of acetic acid, propionic acid, and isobutyric acid. Overall, the results of this study indicate that animal probiotics can be used for beekeeping, and BS was the most effective as a feed additive for honey bees.

Effects of Lactobacillus plantarum on intestinal integrity and immune responses of egg-laying chickens infected with Clostridium perfringens under the free-range or the specific pathogen free environment

BackgroundNecrotic enteritis, which is caused by Clostridium perfringens, has resulted in more than $2 billion losses in the poultry industry every year. Due to the ban of antibiotics in feed industry, alternatives like environment improvement and probiotics have been found to be effective as well. In our study, we aim to explore the protective effect of Lactobacillus plantarum supplementation on CP infected chickens in two environments.ResultsThe results showed that the Clostridium perfringens administration led to visible and histomorphological gut lesions. In the specific pathogen free or free-range system environment, dietary supplementation with LP obvious increased the ratio of intestinal villus height to crypt depth and the expression of MUC2 mRNA in ileum mucosa, then reduced the mRNA expression level of TNF-α gene in the ileum mucosa. LP treatment significantly reduced the contents of total protein, total superoxide dismutase and glutamic oxaloacetic transaminase in serum of the chickens.ConclusionsThe specific pathogen free environment contributed to the recovery of pre-inflammation of the chickens, and free-range system environment contributed to the repair of damage in the later stages of chicken inflammation. Supplementation of LP in FRS environment was more conducive to the recovery of CP infected in chickens.

The Facilitating Effect of Tartary Buckwheat Flavonoids and Lactobacillus plantarum on the Growth Performance, Nutrient Digestibility, Antioxidant Capacity, and Fecal Microbiota of Weaned Piglets.

Simple SummaryThere has been a growing interest in the use of flavonoids and probiotics as alternatives of antibiotics in livestock production and as natural products for human health benefit. The effect of tartary buckwheat flavonoid supplementation in the diet has not been clearly investigated. The supplementation of tartary buckwheat flavonoids or Lactobacillus plantarum improved the growth performance, nutrient digestibility, and antioxidant capacity of weaned piglets. In combination, they exhibited a synergistic effect on nutrient digestibility.Natural plant extracts and probiotics has been proved as the most preferred and effective alternatives for antibiotics in animal feeding. The current study aimed to investigate the facilitating effect of tartary buckwheat flavonoids and Lactobacillus plantarum on the growth performance, nutrient digestibility, antioxidant capacity, and microbiota of weaned piglets. Fifty 35-day-old weaned piglets (7.85 ± 0.67 kg) were randomly divided into five treatments with 10 piglets per treatment. Piglets in the negative control (NC) group were fed a basal diet, and others were fed basal diets supplemented with 40 mg/kg of colistin sulfate (positive control, PC), 109 CFU/kg Lactobacillus plantarum (LP), 40 mg/kg of tartary buckwheat flavonoids (BF), and a combination of 109 CFU/kg Lactobacillus plantarum and 40 mg/kg of tartary buckwheat flavonoids (LB). Supplementation of BF increased the average daily gain of piglets in the BF group (p < 0.05). The nutrient digestibility of piglets in the NC group was lower than that in other groups, while the digestibility of gross energy, dry matter, organic matter, and phosphorus of piglets in the LB group was higher than the other four groups (p < 0.05). Compared with the NC and pC group, supplementation of Lp increased the activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-px), and catalase (CAT), while the BF increased the content of IgA and IgM (p < 0.05). Supplementation of colistin sulfate decreased the alpha diversity index, including chao and observed species, while the addition of Lp or combination of Lp and BF increased the abundance of Selenomonas or Mitsuokella in fecal samples, respectively. The results indicated that supplementation of Lactobacillus plantarum can improve the antioxidant capacity, while tartary buckwheat flavones can increase the growth performance and immune ability of weaned piglets. Moreover, in combination, they promote nutrient digestibility.

Supplementation of Lactobacillus plantarum Improves Markers of Metabolic Dysfunction Induced by a High Fat Diet.

Obesity is a prevalent chronic condition in many developed and developing nations that raises the risk for developing heart disease, stroke, and diabetes. Previous studies have shown that consuming particular probiotic strains of Lactobacillus is associated with improvement in the obese and diabetic phenotype; however, the mechanisms of these beneficial effects are not well understood. In this study, C57BL/6J male mice were fed a lard-based high fat diet for 15 weeks with Lactobacillus plantarum supplementation NCIMB8826 (Lp) between weeks 10 and 15 ( n = 10 per group). Systemic metabolic effects of supplementation were analyzed by NMR metabolomics, protein expression assays, gene transcript quantification, and 16S rRNA marker gene sequencing. Body and organ weights were not significantly different with Lp supplementation, and no microbiota community structure changes were observed in the cecum; however, L. plantarum numbers were increased in the treatment group according to culture-based and 16S rRNA gene quantification. Significant differences in metabolite and protein concentrations (serum, liver, and colon), gene expression (ileum and adipose), and cytokines (colon) were observed between groups with increases in the gene expression of tight junction proteins in the ileum and cecum and improvement of some markers of glucose homeostasis in blood and tissue with Lp supplementation. These results indicate Lp supplementation impacts systemic metabolism and immune signaling before phenotypic changes and without large-scale changes to the microbiome. This study supports the notion that Lp is a beneficial probiotic, even in the context of a high fat diet.

Effects of dietary supplementation of four strains of lactic acid bacteria on growth, immune-related response and genes expression of the juvenile sea cucumber Apostichopus japonicus Selenka

A feeding experiment was conducted to evaluate the effects of four strains of lactic acid bacteria (LAB) [i.e. Lactobacillus plantarum LL11 (LP), Weissella confuse LS13 (WC), Lactococcus lactis LH8 (LL) and Enterococcus faecalis LC3 (ES)] isolated from marine fish on growth, immune response and expression levels of immune-related gens in body wall of juvenile sea cucumber Apostichopus japonicus. As a result, sea cucumber had better growth performance fed supplementation of LP and ES than the control group (P < .05). Survival rate in each LAB supplementation group was significantly higher than that in control group after Vibrio splendidus challenge (P < .05). In regards to the enzyme activities, LP supplementation significantly imporved the enzyme activities of alkaline phosphatase (AKP) (P < .05), acid phosphatase (ACP) and superoxide dismutase (SOD), ES supplementation significantly imporved AKP activity (P < .05), and WC supplementation significantly imporved ACP activity (P < .05). However, lysozyme (LSZ) activity was not significantly changed in the four LAB supplementation treatments (P > .05). For the gene expression levels, different expression patterns were observed among four groups, heat shock proteins (HSP60, HSP70 and HSP90) and caspase-2 showed dramatic up-regulation at 30 d while NF-kappa-B transcription factor p65 was down-regulated at 15 d and up-regulated at 30 d, and nitric oxide synthase was down-regulated at both timepoints in almost all the four groups. In conclusion, the four LAB strains screened from marine fish supplemented in diets indicated positive effects on immune response for A. japonicus, especially, the L. plantarum LL11 and E. faecalis LC3 indicated better growth performance.

Systemic Metabolomic Changes in Mice Fed a High Fat Diet and Supplemented with Lactobacillus plantarum

Metabolic syndrome (MetS) is one of the most prevalent chronic conditions in developed nations and is characterized by a group of factors that raise the risk for developing heart disease, stroke, and diabetes. It has previously been shown that ingestion of certain strains of Lactobacillus are associated with improvement in MetS risk factors, however the mechanisms of these beneficial effects are largely unknown. In this study, C57BL/6J male mice were fed a lard‐based high fat diet (45% of calories from fat) for nine weeks followed by supplementation with Lactobacillus plantarum WCFS1 (Lp) for six weeks (n=10 per group). NMR metabolomics, gene expression, and microbiota composition were analyzed to assess the systemic effects of probiotic supplementation. Significant differences in metabolite concentrations (including amino acids in serum and colon contents) and gene expression (including tight junctions in intestine and inflammation in adipose) were observed between groups. No significant differences were found in body or organ weight with Lp supplementation and no global microbiota structure changes were observed in the cecum; however, a significantly greater abundance of OTUs aligning to Lactobacillus plantarum were observed in the treatment group. These results indicate Lp supplementation impacts systemic phenotype without broad changes to the microbiome. Furthermore, this study supports the notion that consumption of Lp may be beneficial in the context of a high fat diet.Support or Funding InformationFunding was provided by the American Diabetes Association.

Ionophore strategy affects growth performance and carcass characteristics in feedlot steers.

One hundred ninety-two steers (BW = 354 ± 23.5 kg) were used in a randomized block design to evaluate the effects of ionophore and ractopamine hydrochloride (RH) supplementation strategies on performance and carcass characteristics. Twelve pens of 4 steers were assigned to each of the following treatments: unsupplemented control (CON), laidlomycin propionate (12.1 mg/kg DM) with or without RH (LPRH and LP, respectively), and monensin sodium (36.4 mg/kg DM) with RH (MSRH). Steers were fed for 151 d, of which respective treatments received RH (Actogain; Zoetis, Florham Park, NJ) at a rate of 300 mg/(animal · d) for the final 32 d. Laidlomycin was removed from the LPRH treatment during this period, as no combination feeding has been approved. Upon harvest, carcass data were collected by trained personnel, and subsequent analysis of the LM was conducted to estimate tenderness using Warner-Bratzler shear force (WBSF). Prior to RH supplementation, both LP and LPRH had greater ADG ( ≤ 0.02) and G:F ( < 0.01) than CON, whereas MSRH was intermediate. During the final 32 d, MSRH improved G:F ( ≤ 0.02) compared to all other treatments and tended to increase ADG over unsupplemented controls ( = 0.05). Cattle receiving LP without RH had significantly greater BW at d 151 than CON ( = 0.02), whereas both RH treatments tended to improve final BW ( ≤ 0.09). Ionophores improved ADG ( ≤ 0.03) and G:F ( < 0.01) for the entire feeding period, and although LP-supplemented cattle had greater DMI for the final 32 d than both RH treatments ( ≤ 0.01), intakes for the 151-d trial were similar among treatments. Carcass weights were greater ( = 0.04) in cattle fed LP with no RH than CON, where cattle yielded an average of 12 kg more HCW. Ractopamine increased LM area in MSRH-supplemented cattle ( = 0.03) and tended to increase LM area for steers receiving LPRH ( = 0.07). Longissimus steaks of MSRH-supplemented cattle had greater WBSF values than CON ( = 0.04) after 7 d of postmortem aging and greater WBSF values than LPRH steaks after 28 d ( = 0.03). All other carcass and WBSF measurements were similar among treatments. The results of this study indicate that LP supplementation without RH may yield a performance similar to and carcass responses associated with the administration of a β-agonist. These results also suggest that performance and carcass characteristics for cattle fed LP are similar to those of cattle fed monensin throughout the feeding period.

NMR‐Based Metabolomic Profiles of Mice Fed a High Fat Diet and Supplemented with Resistant Starch and/or Lactobacillus

Incidence of obesity and type 2 diabetes mellitus (T2DM) is steadily increasing, and the contributions of diet and the gastrointestinal microbiota to these diseases are only partially understood. Enriching particular populations of microbes in a mouse model of pre‐diabetes and monitoring systemic metabolic effects will help to elucidate the mechanisms of obesity and T2DM progression. C57BL/6J mice were fed a 45% high fat diet for nine weeks and then supplemented with type 2 resistant starch (RS), Lactobacillus plantarum (Lp), or both for six weeks (n=10 per group). Urine was collected throughout the experiment; cecal contents and serum were obtained at the time of mouse sacrifice. All samples were analyzed using NMR‐based metabolomics. Unsupervised principal component analysis showed clear separation between RS and non‐RS groups for both cecal and serum samples. Significant differences were observed for microbial metabolites and amino acids when comparing RS groups to control, as well as when comparing Lp supplementation alone to RS supplementation alone. These results have implications for monitoring the effects of dietary supplementation on the gastrointestinal microbiota and overall host health. Funding was provided by the American Diabetes Association.

Time and dose-dependent effects of Labisia pumila on the bone strength of postmenopausal osteoporosis rat model.

BackgroundPost-menopausal osteoporosis has long been treated and prevented by estrogen replacement therapy (ERT). Despite its effectiveness, ERT is associated with serious adverse effects. Labisia pumila var. alata (LP) is a herb with potential as an alternative agent to ERT due to its phytoestrogenic, antioxidative and anti-inflammatory effects on bone. This study aimed to determine the effects of LP supplementation on bone biomechanical strength of postmenopausal osteoporosis rat model.MethodsNinety-six female Sprague–Dawley rats aged 4 to 5 months old were randomly divided into six groups; six rats in the baseline group (BL) and eighteen rats in each group of; Sham- operated (Sham), ovariectomised control (OVXC) and ovariectomised with daily oral gavages of Premarin at 64.5 μg/kg (ERT), LP at 20 mg/kg (LP20) and LP at 100 mg/kg (LP100) respectively. These groups were subdivided into three, six and nine weeks of treatment periods. Rats in BL group were euthanized before the start of the study, while other rats were euthanized after completion of their treatments. Femora were dissected out for biomechanical strength analysis using Instron Universal Model 5848 Micro Tester.ResultsOVXC group showed deterioration in the bone biomechanical strength with time. Both ERT and LP supplemented rats showed improvements in bone strength parameters such as maximum load, displacement, stiffness, stress, and Young Modulus. The most improved bone strength was seen in rats given LP at the dose of 100 mg/kg for nine weeks.ConclusionLP supplementation at 100 mg/kg was more effective than ERT in reversing ovariectomy-induced bone biomechanical changes.

The effects of Labisia pumila on postmenopausal osteoporotic rat model: Dose and time-dependent micro-CT analysis.

Postmenopausal osteoporosis is best treated and prevented by estrogen replacement therapy (ERT). Although effective, ERT may cause breast cancer, uterine cancer and cardiovascular problems. Labisia pumila var. alata (LP), a herb with phytoestrogenic, antioxidative and anti-inflammatory effects has potential as an ERT alternative. This study aimed to evaluate micro-CT analysis on the effects of LP supplementation on the trabecular microarchitecture of postmenopausal osteoporosis rat model. Micro-CT is an effective tool in detecting changes in trabecular bone structure and providing a three dimensional information which may replace other conventional bone analysis methods. Ninety-six female Sprague-Dawley rats (4 to 5 months old) were randomly divided into six groups of baseline group (BL) Sham-operated (Sham), ovariectomised control (OVXC), ovariectomised with 64.5 μg/kg of Premarin (ERT), ovariectomised with 20 mg/kg of LP (LP20) and ovariectomised with 100 mg/kg of LP at (LP100). The vehicle (deionized water), Premarin and LP were given via daily oral gavages for three, six and nine weeks of treatment periods. Rats in BL group were euthanized before the start of the study, while other rats were euthanized after completion of their treatments. Femora were dissected out and trabecular bone microarchitecture analysed with micro-CT. Micro-CT analysis of OVXC rats revealed significant osteoporotic changes in connectivity density, trabecular bone volume, trabecular thickness, trabecular separation and trabecular number. Both ERT and LP were able to reverse all the OVX-induced bone changes with the best results seen with 100 mg/kg of LP for nine weeks duration of treatment. Micro-CT provides accurate and reliable information on trabecular bone parameters which aid in the diagnosis and treatment of osteoporosis. LP supplementation at 100 mg/kg was more effective than ERT in reversing ovariectomy-induced bone changes. Further studies are required to explore the potential of LP as ERT alternative in the treatment and prevention of postmenopausal osteoporosis.

Labisia pumila protects the bone of estrogen-deficient rat model: A histomorphometric study

Ethnopharmacological relevanceLabisia pumila var. alata (LP) is a phytoestrogenic herb with potential as an alternative to Estrogen Replacement Therapy (ERT) in the treatment of postmenopausal osteoporosis. LP has been reported to produce similar effects to ERT on the bone markers, but could not match ERT in terms of maintaining the bone calcium in postmenopausal osteoporosis rat model. This study aimed to examine in detail the effects of LP on the bone of postmenopausal osteoporosis rat model using bone histomorphometry. Materials and methodsThirty two female rats were randomly divided into groups of: Sham operated (Sham), ovariectomized control (OVXC), ovariectomized with Labisia pumila var. alata (LP) and ovariectomized with ERT (Premarin®) (ERT). The LP and ERT were administered through the route of oral gavage daily at the dose of 17.5mg/kg and 64.5μg/kg respectively. Following 2 months of treatment, rats were euthanized and the left femurs were dissected out and prepared for bone histomorphometry. ResultsHistomorphometric analysis revealed osteoporotic changes for the ovariectomized rats. Supplementation of LP to ovariectomized rats could prevent these osteoporotic changes, as effective as ERT. ConclusionThis confirmed that LP has potential as an alternative to ERT for prevention of postmenopausal osteoporosis.

Influence of dietary magnesium level on growth-performance and metabolic responses of Holstein steers to laidlomycin propionate.

We used 216 Holstein steers (151 kg) in a 262-d trial to evaluate the influence of dietary magnesium level (.19, .25, and .32%) and laidlomycin propionate (LP; 0 vs 11 ppm, air-dry basis) on growth performance and NE value of the diet. During the initial 112 d of the trial, LP increased (P < .01) ADG (6.3%) and feed efficiency (4.2%). From d 112 until slaughter, LP increased (P < .05) ADG (9.7%) and feed efficiency (4.5%). Across the 262-d feeding period, LP supplementation enhanced (P < .01) ADG (8.9%) and feed efficiency (6.3%). There was an interaction (P < .05) between dietary Mg and LP on NE value of the diet. The enhancement in NE value of the diets owing to LP with .19, .25, and .32% dietary Mg were .5, 3.0, and 5.9%, respectively. Six Holstein steers (302 kg) were used in a 6 x 6 Latin square experiment to evaluate treatment effects on characteristics of ruminal and total tract digestion. There were no treatment interactions (P > .10) on site and extent of digestion of OM, starch, and N. Supplemental Mg increased (quadratic effect, P < .10) ruminal OM digestion. Neither LP nor dietary Mg level affected (P > .10) ruminal digestion of starch and feed N. Supplemental LP decreased (15%, P < .05) ruminal microbial efficiency. Total tract digestion of OM and N increased (linear effect, P < .01) with increasing dietary Mg level. There were interactions between LP and dietary Mg level on ruminal soluble-Mg concentration (linear effect, P < .01) and Mg absorption (quadratic effect, P < .05). Apparent total tract Mg digestion increased owing to LP (P < .01) and dietary Mg level (linear effect, P < .01). There were no treatment effects (P > .10) on ruminal pH. Dietary Mg level did not influence (P > .10) ruminal VFA concentrations or molar proportions. Supplemental LP increased (14%; P < .10) total ruminal VFA concentration but did not affect (P > .10) VFA molar proportions. We conclude that LP will increase daily weight gain and feed efficiency of calf-fed Holstein steers and that this response may be enhanced by increasing dietary Mg level.

Oxidation of lipoprotein Lp(a). A comparison with low-density lipoproteins

Aimed at identifying possible mechanisms of the suggested high atherogenicity of Lp(a), its susceptibility for Cu(II)-induced oxidation was studied and compared with that of LDL. Since the content of antioxidants as well as the fatty acid pattern of a lipoprotein greatly affects its oxidizability, Lp(a) and LDL were characterized first with respect to these substances. Paired samples of low-density lipoproteins (LDL) and Lp(a) were isolated from seven individual donors and compared with each other. This study showed that LDL and Lp(a) are very similar with respect to their fatty acid and antioxidant composition. LDL contains approx. 1132 nmol of total fatty acids/mg lipoprotein and LDL 1466 nmol total fatty acids/mg lipoprotein. Analysis of the fatty acid composition of individual lipid classes (cholesteryl esters, phospholipids and triacylglycerols) revealed also a high similarity in the composition of these lipid classes between the two lipoproteins. A comparison of the antioxidant composition showed that Lp(a) contains less α-tocopherol than LDL (1.6 ± 0.35 nmol/mg vs. 2.1 ± 0.25 nmol/mg LDL). In copper(II)-induced lipid peroxidation experiments we found a striking difference in the susceptibility of individual lipoprotein classes between all donors. In addition, Lp(a) exhibited a 1.2 to 2.4 longer lag-phase than the corresponding LDL preparation from the same blood donor. Treatment of Lp(a) with neuraminidase resulted in a drastic decrease of thelag-phase of Lp(a). Neuraminidase treatment of LDL on the other hand had no significant effects on its susceptibility to oxidation. Supplementation of neuraminidase-treated Lp(a) with N-acetylneuraminic acid (NANA) at concentrations comparable to the naturally occurring amounts of NANA in the Lp(a) protein moiety led to an increase of the lag-phase yielding values which were comparable to those observed with native Lp(a). These results demonstrate that the fatty acid composition as well as the antioxidant concentrations of Lp(a) and LDL are quite similar; despite this fact, Cu 2+-mediated oxidation of Lp(a) is retarded in comparison to LDL which might be due to the higher content of NANA in Lp(a).