Stanisława Raj

Profile of fatty acids, muscle structure and shear force of musculus longissimus dorsi (MLD) in growing pigs as affected by energy and protein or protein restriction followed by realimentation

Forty-eight gilts were submitted to a 30% restriction of feed (groups F and F1) or protein intake (group P) from 90 to 118 days of age, followed by realimentation from 119 to 168 days of age. Control pigs (C) were fed during the whole experiment according to a semi ad libitum scale. During realimentation all animals were fed according to semi ad libitum scale except pigs F1 which were fed ad libitum. Six pigs from each group were slaughtered at the end of restriction and realimentation. Restriction decreased the weight of musculus longissimus dorsi (MLD) and increased shear force. Restriction of feed intake depressed MUFA concentration and increased n-6/n-3 ratio while protein restriction decreased n-6/n-3 and PUFA:SFA ratios. Structure of fibers was not affected. After realimentation MLD mass was still lower in all previously restricted pigs, shear force was the lowest in F1 pigs. Only percentage of fast twich oxidative fibers was significantly greater in F1 pigs than in others. Significant correlations between parameters investigated during the study were found.

Omega-6 and omega-3 fatty acids metabolism pathways in the body of pigs fed diets with different sources of fatty acids

This study was carried out on 24 gilts (♀ Polish Large White × ♂ Danish Landrace) grown with body weight (BW) of 60 to 105 kg. The pigs were fed diets designed on the basis of a standard diet (appropriate for age and BW of pigs) where a part of the energy content was replaced by different fat supplements: linseed oil in Diet L, rapeseed oil in Diet R and fish oil in Diet F (6 gilts per dietary treatment). The fat supplements were sources of specific fatty acids (FA): in Diet L α-linolenic acid (C18:3 n−3, ALA); in Diet R linoleic acid (C18:2 n−6, LA) and in Diet F eicosapentaenoic acid (C20:5 n−3, EPA), docosapentaenoic acid (C22:5 n−3, DPA) and docosahexaenoic acid (C22:6 n−3, DHA). The protein, fat and total FA contents in the body did not differ among groups of pigs. The enhanced total intake of LA and ALA by pigs caused an increased deposition of these FA in the body (p < 0.01) and an increased potential body pool of these acids for further metabolism/conversions. The conversion efficiency of LA and ALA from the feed to the pig’s body differed among groups (p < 0.01) and ranged from 64.4% to 67.2% and from 69.4% to 81.7%, respectively. In Groups L and R, the level of de novo synthesis of long-chain polyunsaturated FA was higher than in Group F. From the results, it can be concluded that the efficiency of deposition is greater for omega-3 FA than for omega-6 FA and depends on their dietary amount. The level of LA and ALA intake influences not only their deposition in the body but also the end products of the omega-3 and omega-6 pathways.

Protein, nucleic acid content and activity of μ- and m-calpain in the longissimus dorsi muscle as affected by protein and energy restriction during early growth of pigs

The study was conducted to determine the changes in growth rate, protein deposition, concentration of nucleic acids, and activity of calpain enzymes in the longissimus dorsi muscle of pigs, which received a low protein and low energy diet from 25–50 kg bodyweight (BW) followed by adequate feeding to 105 kg BW in comparison with pigs fed adequately throughout the study. The muscle of pigs subjected to limitation tended to grow slower and deposit less protein daily (by 25%, p < 0.10), but have a significantly lower DNA concentration (by 13%, p < 0.01). The activity of μ- and m-calpain was also significantly lower compared with control pigs (0.942 vs. 1.92 and 0.246 vs. 0.403 U/g, respectively). After resumption of adequate feeding, the daily gain of muscle and protein deposition did not differ from control pigs. Moreover, at 80 kg and 105 kg BW the DNA and RNA concentration as well as the activity of m-calpain and μ-calpain did not differ between groups.

Bone mineralisation of weaned piglets fed a diet free of inorganic phosphorus and supplemented with phytase, as assessed by dual-energy X-ray absorptiometry.

Sixteen female piglets (58 d of age, 16.8 ± 0.8 kg body weight [BW]) were assigned to two groups (n = 8) and received until day 100 of age (50.3 ± 1.2 kg BW) ad libitum either a diet with a standard (diet C) or low (diet L) total phosphorus (P) content (5.38 and 4.23 g/kg, respectively). Diet C was supplemented with mineral P (1.15 g/kg) and did not contain microbial phytase. Diet L did not contain any inorganic P but 750 FTU/kg of microbial phytase. Despite these treatments, both diets were composed with the same ingredients. Body mineralisation of each gilt was assessed by determining the bone mineral content (BMC), area bone mineral density (BMD) by the dual-energy X-ray absorptiometry (DXA) at days 58, 72, 86 and 100 of age. Feeding diet L caused a higher P digestibility (p = 0.008) measured from days 72 to 86 of age and at 100 days of age a higher BMC and BMD (p ≤ 0.01). Furthermore, the gilts of group L deposited more minerals in the body than control pigs (by 2.4 g/d, p = 0.008). It was found that BMD and BMC were positively correlated with body lean mass and digestible P intake. The results indicated that, even for very young pigs, the addition of microbial phytase instead of inorganic P increases the amount of digestible P covering the requirements of piglets for proper bone mineralisation. Furthermore, it was proved that the DXA method can be successfully applied to measure body fat and lean mass contents as well as bone mineralisation of growing pigs using the same animals.

Effect of nutritional regulation of growth on histochemical characteristics of muscles in pigs

Abstract The aim of the experiment was to determine the effect of different strategies of pig nutrition (restriction and realimentation) on histochemical traits in Longissimus lumborum (LL), Biceps femoris (BF) and Semitendinosus (ST) muscles. Reduced energy and protein intake contributed to a significant decrease in the weight of LL muscles during controlled growth and in the weight of LL, BF and ST muscles at 168 days of age. After the restricted feeding period, it was found that reduced intake of protein and energy or of protein alone had a significant effect on the proportion and diameter of fast-twitch glycolytic (FTG) fibres. After realimentation, no differences in muscle structure were found between the investigated groups of animals. Regardless of the feeding system, the growth of pigs was paralleled by hypertrophy of all muscle fibre types and their different transformation in the muscles.

Relationship between pork fatty acid content in selected muscles and carcass tissues

Pork plays a central role in culinary tradition in Central Europe. Most of the studies determine the fatty acid (FA) content separately in muscles and subcutaneous fat. However, it is also important to determine the FA content of meat products, which contain a mixture of muscles and fat. The determination of FA in carcass tissues is difficult and leads to the destruction of the whole carcass. Thus, the aim of this study was to estimate the FA content of carcass meat (muscles with inter- and intramuscular fat, MC), and carcass soft tissues (muscles with inter- and intramuscular fat and subcutaneous fat, SC) based on a single muscle. Fatty acids were analysed using gas chromatography. Thirty crossbred pigs were fed diets differing in their fatty acid content and n-6 : n-3 polyunsaturated fatty acid (PUFA) ratio. Samples of Longissimus thoracis et lumborum (LL), Biceps femoris (BF), Semitendinosus (ST), and Semimembranosus (SM) muscles, MC, and SC were taken. Correlation between linolenic, eicosapentaenoic and docosahexaenoic acids contents and n-6 : n-3 PUFA in examined muscles and MC ranged from 0.809 (SM) to 0.961 (LL), from 0.708 (LL) to 0.954 (ST), from 0.907 (SM) to 0.941 (ST), respectively (P = 0.000). Correlation between linolenic, eicosapentaenoic and docosahexaenoic acids contents and n-6 : n-3 PUFA in examined muscles and SC ranged from 0.773 (SM) to 0.954 (LL), 0.763 (LL) to 0.983 (BF), and from 0.909 (LL) to 0.940 (ST), respectively (P = 0.000). Results allow estimate the FA content of MC and SC based on their content in single muscles.

Femur morphometry, densitometry, geometry and mechanical properties in young pigs fed a diet free of inorganic phosphorus and supplemented with phytase

ABSTRACT The study investigated in piglets the effect of replacing dietary inorganic P by addition of microbial phytase and its impact on performance, nutrient digestibility and on the geometrical characteristics and mineralisation of the femur. Sixteen pigs on day 58 of age were divided into two groups and fed either a diet free of additional inorganic phosphorus (P) and supplemented with phytase (Diet LP, 4.23 g total P/kg diet) or a diet with a mineral source of P and not supplemented with phytase (Diet SP, 5.38 g total P/kg diet). Performance data and the apparent total tract digestibility of nutrients were estimated between days 58 and 114, and 72 and 86 of age, respectively. On day 114 of age, the pigs were slaughtered, the femur was dissected and the mineral content and mineral density, maximum strength and maximum elastic strength, cortical wall thickness, cross-sectional area and cortical index were analysed. The growth performance and digestibility of nutrient fractions (with exception of P) did not differ between treatment groups. The P-digestibility was significantly higher in Group LP. The femur of pigs in Group LP had significantly greater cortical wall thickness, cortical index, bone mineral content, bone mineral density, maximum strength and maximum elastic strength than Group SP. Femur maximum strength and maximum elastic strength were correlated with cortical wall thickness and cortical index. Resulting from the different supply of digestible P, the femur geometrical, densitometric and mechanical properties of Group LP were better than those of Group SP. The mechanical properties of the femur of pigs depended more on its geometrical characteristics than on the degree of its mineralisation.

Effects of dietary fat on the saturated and monounsaturated fatty acid metabolism in growing pigs

ABSTRACT The effect of dietary fats differing in fatty acid (FA) composition on the metabolism of saturated FA (SFA) and monounsaturated FA (MUFA) in growing pigs was investigated. The deposition of FA in the body and the fate of individual dietary FA were assessed after slaughter. Gilts with an initial body weight (BW) of 60 kg were used as experimental animals. Six pigs were slaughtered at 60 kg BW, while further 18 pigs received three isoenergetic and isonitrogen experimental diets containing linseed oil, rapeseed oil or beef tallow at 50 g/kg diet until they reached 105 kg (six pigs per group). The chemical composition and the content of FA in the whole body were determined and compared across groups. Regardless of dietary treatment, the whole body contained similar amounts of protein, fat and total FA. The total accumulation (percentage of net intake and de novo production) of SFA and MUFA was similar in all groups, but the processes of elongation and desaturation of SFA and MUFA depended upon the type of FA added to the diet. A high dietary content and intake of MUFA inhibits desaturation compared to SFA- and PUFA-rich diets, whereas a high SFA content and intake lowers elongation rate. The increasing net intake of total SFA and MUFA was associated with a lower total de novo production of these FA in the whole body of pigs.

The effect of glucosinolate fraction concentrations in rapeseed meal on daily protein deposition in the body and on internal organ weights of growing pigs

Thirty-five gilts weighing 25 kg were divided into five groups and until reaching 70 kg fed with isoenergetic diets based on cereals and rapeseed meal differing in the content of glucosinolate fractions. Daily protein deposition in the body, weight of thyroid glands, liver, kidneys, and T3 and T4 hormone levels in the blood were measured as affected by the concentration of alkenyl(alk-) and indole(ind-) glucosinolates (GL). Daily protein deposition in the body decreased (by 8.5 %, statistically nonsignificant), but the weight of internal organs increased (thyroid glands by 210%, P O . 0 0 1 ; liver by 50%, P O . 0 1 , and kidneys by 17%, PO.05 ) as the alkand ind-GL concentration in the diets rose (from 0.52 to 2.10 and from 0.17 to 0.40 mmoles kg1 , respectively). The correlation coefficients (partial) indicated that the concentration of indhad a greater influence on weight of internal organs than alk-GL. Indoleand alkenyl-glucosinolates had a similar effect on the level of T3and T4 hormones in the blood, but did not influence protein deposition.