J. Kowalczyk

The simple and sensitive measurement of malondialdehyde in selected specimens of biological origin and some feed by reversed phase high performance liquid chromatography

A method for the determination of malondialdehyde (MDA) concentrations in specimens of animal tissues and feed has been developed using high performance liquid chromatography. The MDA concentration in acidified urine samples was determined after its conversion with 2,4-dinitrophenylhydrazine (DNPH) to a hydrazone (MDA-DNPH). Samples of blood plasma, muscle, liver and feed were prepared by saponification followed by derivatisation with DNPH to MDA-DNPH. The MDA concentration in chicken and hen feed samples was analysed after saponification and derivatisation followed by extractions with hexane. The free MDA in plasma samples was determined after deproteinization followed by derivatisation of MDA with DNPH. The chromatographic separation of MDA-DNPH samples was conducted using Phenomenex C(18)-columns (Synergi 2.5 μm, Hydro-RP, 100 Å, the length of 100mm) with an inner diameter of 2 or 3mm. MDA in processed biological samples was analysed using a linear gradient of acetonitrile in water, and the photodiode detector was set to 307 or 303 nm for detection. The current method that was utilised was based on the high-efficient derivatisation of MDA and was more sensitive compared to previously used methods. The selective and sensitive photodetection of the column effluent was found to be suitable for the routine analysis of MDA in urine, plasma, muscles and liver of animals and some feed samples. Because urine or blood plasma samples can be derivatised in a simple manner, the proposed method can also be suitable for the routine, non-invasive evaluation of oxidative stress in animals and humans.

Rumen degradability of crude protein of dried grass and lucerne forage measured by in sacco incubation and predicted by near infrared spectroscopy

Abstract Samples of grass (16) and lucerne (38) were harvested in advancing maturity and growth stages within 1 year from April to October and were used to test the applicability of near infrared reflectance spectroscopy (NIRS) to estimate ruminal degradability of crude protein (CP). CP degradability characteristics were measured with cows using the nylon bag techniques. Changes in the nutrient contents were consistent with vegetation stage in the primary growth of grass and lucerne and the first regrowth of lucerne. Total degradability a + b was higher in lucerne forage than in grass. The means (± SE) for four growth cycles of lucerne up to full bloom stage were 92.5 ± 4.28, 93.9 ± 2.05, 94.0 ± 0.60 and 96.1 ± 1.41, compared with 90.0 ± 5.98 and 90.6 ± 2.52 for grass up to anthesis in two cycles. Effective CP degradability ( ED ) of both grass and lucerne decreased with increasing maturity. Up to late blooming stage ED values were between 70 and 82% for grass and 80–90% for lucerne. In the primary growth samples, linear relationships ( P a + b and ED ( Y ) and the content of CP, crude fibre (CF) and the day of vegetation ( X ). Up to the end of bloom stage, for ED : R 2 ranged between 0.85 and 0.94 and SE between 0.78 and 2.9; for a + b the respective values were 0.89–0.97 and 0.59–3.2. NIRS was shown to be more universal than CP and CF content in prediction of ED and a + b values of dried forage. Based on a common calibration at five wavelength terms for combined samples of grass and lucerne ( n = 54), ED and a + b of all samples could be predicted with a mean standard error of 2.59 and 3.27. NIR data accounted for 0.9 and 0.87 of variability in ED and a + b values in all samples of grass and lucerne.

Dietary carbohydrates affect caecal fermentation and modify nitrogen excretion patterns in rats. I. Studies with protein-free diets.

In a two‐factorial experiment on 96 young male rats, the effects of substituting 10% raw potato starch (PS), pectins (PEC), or cellulose (CEL) for corn starch (CS) were studied using an unsupplemented protein‐free (PF) diet or a PF diet supplemented either with DL‐methionine or urea. The pH and the short chain fatty acids (SCFA) content in caecal digesta, as well as caecal digesta and tissue weights were determined and used as the criteria of caecal fermentation intensity. Blood urea level, amount of N excreted via faeces and urine, DAPA content, and amino acid composition of faecal protein were analyzed as indices of protein metabolism. A 10‐day adaptation period to the carbohydrates fed with the casein diet preceded the experimental period of feeding the respective carbohydrates with protein‐free diets. Dietary carbohydrates significantly influenced total and individual SCFA content in caecal digesta, as well as other parameters related to the intensity of fermentation. Potato starch and pectins were more intensively fermented than cellulose. Supplementation of the PF diet with methionine and urea affected only caecal isobutyric and valeric acid content in a way dependent on the carbohydrates present in the diet. Carbohydrates significantly altered the routes of N excretion. Faecal excretion was increased by all carbohydrates studied compared to corn starch, pectins had the most marked effect. Urinary excretion was significantly increased by cellulose (as compared with the PEC and PS groups) and decreased by pectins as compared with all other groups. There was an interaction between the effects of carbohydrates and type of protein‐free diet on faecal and urinary excretion. The sum of amino acids in faecal protein was the lowest on the PEC diet, but the amino acid composition expressed as a per cent of total amino acid content was similar in all groups. It can be concluded that dietary carbohydrates alter the excretion patterns of endogenous nitrogen in rats in different ways and that this effect is related to the intensity of their fermentation in the hind gut.

Dietary carbohydrates affect caecal fermentation and modify nitrogen excretion patterns in rats II. Studies with diets differing in protein quality

In 2 two‐factorial experiments, each conducted on 80 growing male rats, the effects of substituting 10% raw potato starch (PS), pectins (PEC), or cellulose (CEL) for wheat starch (WS) and the addition of tannic acid to WS (WSTA) were studied using diets differing in protein quality. Casein unsupplemented or supplemented with DL‐methionine and gluten unsupplemented or supplemented with lysine, methionine and tryptophan were used as protein sources in Experiment 1 and 2, respectively. Parameters indicative of caecal fermentation intensity (pH, acetic, propionic and butyric acid contents, digesta and tissue weight) and of protein metabolism (urea blood concentration, faecal and urinary nitrogen excretion) were determined. Ten‐day balance experiments were preceded by a 10‐day adaption period to respective carbohydrates given in a diet containing balanced protein. In both experiments the type of carbohydrates affected the caecal concentration of individual and total SCFA and other parameters of fermentation intensity. Pectins and potato starch were fermented more intensively than cellulose. Faecal N excretion was increased by all carbohydrates substituted for cereal starch, and by tannic acid. Urinary excretion was greater on CEL than on PEC and WSTA containing casein and on other diets containing gluten. In both experiments urinary N excretion was the lowest on PEC diets. Protein quality had the greatest effect on apparent biological value and net protein utilization but all indices of protein utilization were also affected by carbohydrates. It is concluded that not only the amount of N excreted in faeces but also in urine is affected by the type and fermentability of carbohydrates.

The digestion in the small intestine of young bulls of the protein of rapeseed meal treated or untreated with formaldehyde

Twelve bulls of approximately 140 kg bodyweight were each fitted with simple cannulae in the rumen and abomasum and a re-entrant cannula in the terminal ileum. They were kept in individual pens and given daily 1.8 kg of a basal diet containing dried maize meal (whole plant), dried sugarbeet pulp and a urea/mineral preparation in the proportions 0.80, 0.18 and 0.02. Four animals received this diet alone, four received in addition 198 g daily (11 g N) of rapeseed meal by infusion into the abomasum and the remaining four the basal diet plus the same amount of formaldehyde-treated rapeseed also by infusion. The concentration of ammonia-N in the rumen fluid of animals given the untreated rapeseed meal was higher (P < 0.05) than for those on the other two treatments. The pH of the rumen and abomasal fluid was similar on all treatments. Coefficients for the apparent disappearance in the small intestine of the dry matter and nitrogen of untreated rapeseed meal infused into the abomasum were 0.76 and 0.75, respectively. In contrast formaldehyde-treated rapeseed meal was poorly digested. It is suggested that procedures for the treatment of rapeseed meal that will minimise the degradability of its protein in the rumen, yet prevent depression of its digestion and absorption in the abomasum and small intestine have still to be defined.

Zum Problem des Harnstoffeinsatzes in der Schweinefütterung

For a period of 9 days growing fattening pigs (with liveweights ranging from 40 to 50 kgs were fed a ration of autumn barley, dried skim mild and wheat gluten supplemented with 0.5% of 15N labelled urea (12.5% of the total N). The N balance and the rate of 15N protein retention as well as the rates of protein and amino acid synthesis in the different organs and tissues of the carcasses were estimated by emission spectrometry after amino acid fractionation. On an average, 19.3% of the ingested urea were retained, while only 4% N were retained in the essential amino acids found in the carcasses. This proportion will, to a large extent, result from transamination processes and, to a lesser extent, from microbia synthesis. From this it may be concluded that urea N does not induce any appreciable synthesis of amino acids in pigs so that urea cannot be regarded as a suitable substitute for protein feeds in the feeding of monogastric animals.

Efficiency of fatty acid accumulation into breast muscles of chickens fed diets with lycopene, fish oil and different chemical selenium forms

The purpose of the investigation was to determine the effect of the addition of 12 ppm lycopene (Lyc), 2% fish oil (FO) or 0.25 ppm Se as selenate (SeVI) or selenized yeast (SeY) to an isoenergetic and isonitrogenous basal diet containing sunflower oil (SO) as the source of energy on the concentrations of fatty acids (FA), especially saturated- (SFA), mono- (MUFA) and polyunsaturated (PUFA) acids, in breast muscles of female and male chickens for six weeks. The influence of these additives on the capacity of D9-, D4- and D5-desaturations, the elongation of FA, and the yield of PUFA peroxidation (an oxidative stress) in breast muscles of female and male chickens were also studied. Dietary SeY most efficiently decreased the concentrations of SFA, MUFA and PUFA as well as malondialdehyde (the marker of the oxidative stress) in muscles of female and male chickens. The addition of FO most efficiently increased the concentration of n-3 long-chain PUFA (n-3LPUFA) and most effectively increased the concentration ratio of n-3LPUFA to SFA (n-3LPUFA/SFA), while most effectively decreased the concentration ratio of n-6PUFA to n-3PUFA (n-6PUFA/n-3PUFA) in muscles of chickens that are beneficial to human health. We conclude that further studies are necessary to determine if diets containing other chemical form of selenium compounds and other vegetable oils induce changes in the profiles of fatty acids in muscles of chickens that are beneficial to human health. Keywords: Chicken, lycopene, selenium, fish oil, sunflower oil, breast muscles, fatty acids, malondialdehyde African Journal of Biotechnology , Vol 13(14), 1604-1613

Effect of dietary conjugated linoleic acid and selenized yeast on the concentration of fatty acids and minerals in rats

Abstract The main objective of this study was to evaluate the influence of diets enriched in individual conjugated linoleic acid (CLA) isomers, their mixture, and/or selenized yeast (Se-yeast) on the concentration of CLA isomers, long-chain polyunsaturated fatty acids (PUFA) and Se in the heart, muscles and liver of rats. The investigation was performed on 73 female Wistar rats (8 weeks of age, 200 g initial BW). After one week sub-maintenance feeding, rats received diets supplemented with 1% individual CLA isomers or 1 or 2% of a CLA isomers mixture, without or with 1.2 mg Se/kg (as Se-yeast) for 29 days. Feeding diets with 2% CLA isomer mixture reduced feed intake and body weight gain of rats, while addition of trans10,cis12 CLA and Se-yeast resulted in the highest body weight gain. CLA supplementation generally elevated the concentration of CLA isomers in heart and muscles significantly, although cis9,trans11 CLA accumulated preferentially. Regardless of the presence of Se-yeast, the dietary enrichment with CLA isomers caused a reduction in the capacity of Δ9-desaturase. Addition of Se-yeast to diets with individual CLA isomers or a 1% mixture of CLA isomers elevated the accumulation of CLA isomers in the heart and muscles, whereas all treatments with supplemented CLA and Se-yeast increased the accumulation of Se in rats compared with animals fed the diet containing Se only. Furthermore, CLA isomer supplementation decreased the concentration of PUFA and total fatty acids in the heart and muscles compared with control rats. Moreover, addition of CLA isomers interfered in the conversion of linoleic and linolenic acids to higher metabolites due to competition of CLA isomers for the same enzymes (Δ6-, Δ5-, Δ4-desaturases and elongase).

Fatty Acid Profile and Oxidative Stress of Thigh Muscles in Chickens Fed The Ration Enriched in Lycopene, Selenium Compounds or Fish Oil

Abstract The aim of the study was to determine the influence of the addition for 6 weeks of 12 ppm lycopene (Lyc), 2% fish oil (FO) or 0.25 ppm Se as selenate (Sevi) or selenized yeast (SeY) to an isoenergetic and isonitrogenous ration containing sunflower oil as the source of energy on the profile of fatty acids (FA) and the oxidative stress in thigh muscles of female and male chickens. The ration with FO most efficiently increased the concentration of saturated fatty acids (SFA), atherogenic SFA and thrombogenic SFA as well as the concentration sum of all assayed FA in muscles of chickens. the rations with lyc, sevi or SeY revealed negligible and inconsistent impact on the concentration of individual SFA in muscles compared with the control. The ration with FO most efficiently increased the concentration of polyunsaturated FA (PUFA), especially n-3 long-chain PUFA and the sum of conjugated linoleic acid isomers in muscles. The ration with SeY most effectively increased the concentration of long-chain PUFA (LPUFA), especially n-6 LPUFA, in muscles of chickens. the Fo, lyc or sevi-fed chickens had a lower concentration of cholesterol in muscles than the control or SeY fed birds. Lyc added to the ration most efficiently stimulated the accumulation of α-tocopherol in muscles of chickens. The ration with Sevi most effectively stimulated the formation of malondialdehyde in muscles.

The Effect of the Amount of Urea in the Diet on the Contents of Amino Acids and other Components of Duodenal Digesta in Young Bulls

Young bulls of average live weight 130 kg, with rumen cannulae and re-entrant cannulae of the proximal duodenum, were fed on a diet of maize meal from whole plants, potato starch and a mineral mixture, containing 7.6% crude protein in DM (group IV). For three groups the diet was supplemented to contain about 17.5% crude protein with groundnut oilmeal (group I), grundnut oilmeal and urea, 27 and 31.2% of dietary N (group II) or urea alone (group III). The content of gross energy was similar in all diets. The amount of total N entering the duodenum in groups I to IV was 61.6, 59.2, 49.9 and 38.0 g/day and apparent digestibility of N in the stomachs was -0.4, 5.8, 21.6 and -44.4%. Total amount of amino acids in the duodenal digesta was, in the same order, 257, 261, 215 and 170 g/day, equivalent to 80, 116, 165 and 127% of intake. The ratio of the amounts of essential to nonessential amino acids was in feed 0.84 and in duodenal digesta in all groups 0.98. The amount of lysine in duodenal digesta was 1.5, 2.0, 3.5 and 2.5 times its intake in the same order of the groups.