Changes in texture, colour and fatty acid composition of male and female pig shoulder fat due to different dietary fat sources

Integrated Analysis of Long Non-Coding RNA and mRNA to Reveal Putative Candidate Genes Associated with Backfat Quality in Beijing Black Pig

Pigs' backfat quality has an important impact on the quality of pork and pork products and has a strong relationship with nutrition and sensory characteristics. This study aimed to identify the related candidate genes of backfat quality and to preliminary clarify the molecular regulatory mechanism underlying pig backfat quality phenotypes. Expression assessments of long non-coding RNA (lncRNA) and mRNA profiling in backfat from high-quality (firm and white) and low-quality (soft and yellow) Beijing Black pigs were performed by RNA sequencing. Significantly different expressions were observed in 610 protein-coding genes and 290 lncRNAs between the two groups. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway annotation showed that some candidate differentially expressed genes that participate in lipid-related pathways and pigmentation terms may play a role in backfat quality in pigs. The cis-target and trans-target genes were predicted to explore the regulatory function of lncRNAs, and integrative analyses of different expression lncRNAs targets and different expression genes were performed. The results showed the regulatory networks of lncRNA-mRNA related to backfat quality, and our study obtained strong candidate genes for backfat quality: ELOVL5, SCD, DGAT2, SLC24A5, and TYRP1, which were involved in fat metabolism, adipogenesis regulation, and pigmentation. To our knowledge, this study is the first to demonstrate the molecular genetic mechanisms of backfat quality in pigs, and these findings improve the current understanding of backfat quality mechanisms and provide a foundation for further studies.

In Vivo Performances, Carcass Traits, and Meat Quality of Pigs Fed Olive Cake Processing Waste

Simple Summary

In the recent years, the use of agro-industrial by-products in animal feed has been considered to reduce costs coming from the disposing of processing wastes and from the feeding for the animal breeding. The aim of this study was to assess the inclusion of two different levels of olive cake in 72 Pietrain pigs, during the finishing period; animals fed three dietary treatments contained increasing levels of olive cake: 0% (Ctrl), 5% (Low), and 10% (High) as partial substitution of wheat middling and soybean oil. Our hypothesis was that the inclusion of olive cake could be a possible strategy for the following: (i) finding unconventional ingredients of a commercial complete feed, and (ii) improving in vivo and postmortem performances, with particular attention on the acidic profile. The present study demonstrated that feeding olive cake improved animal performances and influenced some qualitative parameters, reducing the deposition of intramuscular fat and modifying the fatty acid composition in the intramuscular fat and backfat, where the concentration of MUFA and PUFA were increased and the quality indices (AI and IT) were improved. Obviously, the inclusion of unconventional ingredients in animal feed should not negatively affect the meat organoleptic characteristics.

Abstract

The aim of the study was to assess the inclusion of different levels of olive cake in pigs’ diet as a strategy to replace conventional ingredients and to improve meat quality traits. Seventy-two Pietrain pigs, during the growing–finishing period (50–120 kg BW), were fed with three dietary treatments that contained or did not contain olive cake: 0% (Ctrl), 5% (Low), and 10% (High). The trial lasted 90 days. Weekly, individual body weight (BW) and feed intake (FI) were recorded to calculate average daily gain (ADG) and feed conversion ratio (FCR). At slaughter, the dressing percentage was calculated and carcass weight and backfat thickness were measured. On a section of Longissimus thoracis muscle (LT), pH, color, chemical, and fatty acid composition were determined. Fatty acid profile was also determined in backfat. The statistical model included the effects of diet (Ctrl, Low, and High). The inclusion of 5% of olive cake in the diet improved significantly (p < 0.05) BW and FCR. Both levels of inclusion (5% and 10%) significantly reduced (p < 0.05) backfat thickness and intramuscular fat and modified their fatty acid composition, increasing (p < 0.05) the concentration of MUFA and PUFA and improving (p < 0.05) quality indices. Results suggest that olive cake did not negatively affect the productive performances.

Meat quality from pigs fed tomato processing waste

Sixteen Nero Siciliano pigs were used to investigate the effect of dietary tomato processing waste on meat quality. During 86 days one group (CON, n = 8) received a pelleted conventional diet, while another group (TOM, n = 8) received the same diet in which tomato waste replaced 15% of corn. The dietary treatment did not affect growth performances. The TOM diet reduced intramuscular fat, SFA and MUFA content, while increasing the n-6:n-3 ratio in meat (P < .05). The TOM diet increased the concentration of PUFA, PUFA n-3, PUFA n-6 and the n-6:n-3 ratio (P < .01). The instrumental colour descriptors of backfat were unaffected by diet. The TOM diet increased deposition of retinol in meat (P < .001) but did not affect oxidative stability parameters measured in fresh meat and meat homogenates with pro-oxidant catalysts. Concluding, tomato pomace fed to pigs at higher levels compared to previous reports had no adverse effects on the investigated meat quality traits.

The effect of inulin supply to high-fat diet rich in saturated fatty acids on pork quality and profile of sarcoplasmic protein in meat exudate

The aim of the study was to evaluate the influence of inulin supply to high-fat diet rich in saturated fatty acids (SFA) on pork quality and profile of sarcoplasmic protein in drip loss. At 50 days of age, twenty cross-bred pigs (gilts) were randomly allotted to four groups: the control (C) group fed a standard diet, and three experimental (D1, D2 and D3) groups fed a high-fat diet rich in SFA. Moreover, pigs from the groups D2 and D3 consumed an extra inulin supply (7% of daily feed intake) from 85 to 120 days of age (for 5 weeks) and from 50 to 120 days of age (for 10 weeks) respectively. The addition of inulin to the diet reduced meaty odour and flavour significantly, improved tenderness and overall sensory quality of pork and additionally influenced ultimate pH, L* colour parameter, lactate level and protein content in meat. The diets also affected the profile of sarcoplasmic proteins. Significant effects were observed for the following enzymes-PK/PGI (pyruvate kinase/phosphoglucose isomerase) and ALD (aldolase), which are related to the intensity of post-mortem glycolysis. Presented data indicate that long-term inulin supply to high-fat diet has a positive effect on technological and sensory quality as well as protein profile of pork.

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.

Lipolysis and aroma generation as mechanisms involved in masking boar taint in sodium reduced fermented sausages inoculated with Debaryomyces hansenii yeast

BACKGROUND

The use of boar back fat for processing of fermented sausages may cause the presence of abnormal odours. In dry-cured products, ripening time is essential to develop the sensory characteristics. Yeast has been proposed as an alternative to mask boar taint odour through its metabolic activity but it is necessary to elucidate which mechanisms are involved. The aim is to study the effect of Debaryomyces hansenii inoculation on the lipolysis process and generation of aroma compounds in fermented sausages manufactured with boar back fat at two different ripening times.

RESULTS

D. hansenii inoculated sausages had a higher degree of lipolysis as demonstrated by higher content of free fatty acids, ester compounds and branched aldehydes which contribute the fruity odour. The increase in lipolysis produced by D. hansenii inoculation was not followed by an increase in oxidation during processing possibly due to the metabolic activity of yeast. The effect of back fat type was scarcely appreciated whereas ripening time had a stronger effect on sausage. Boar sausages were characterised by a lower polyunsaturated fatty acid profile and lesser lipolysis than gilt sausages.

CONCLUSION

Yeast inoculation with D. hansenii and long ripening time were appropriate strategies to limit the perception of boar taint in dry fermented sausages. © 2017 Society of Chemical Industry.

Influence of dietary fat source and feeding duration on finishing pig growth performance, carcass composition, and fat quality

A total of 160 finishing pigs (PIC 327 × 1050; initially 45.6 kg) were used in an 84-d experiment to evaluate the effects of dietary fat source and feeding duration on growth performance, carcass characteristics, and carcass fat quality. There were 2 pigs per pen with 8 pens per treatment. The 10 dietary treatments were a corn-soybean meal control diet with no added fat and a 3 × 3 factorial with main effects of fat source (4% tallow, 4% soybean oil, or a blend of 2% tallow and 2% soybean oil) and feeding duration (d 0 to 42, 42 to 84, or 0 to 84). The control corn-soybean meal diet was fed in place of added fat diets when needed for duration treatment purposes. On d 0, 1 pig was identified in each pen and fat biopsy samples of the back, belly, and jowl were collected on d 0, 41, and 81 for fatty acid analysis. At the conclusion of the study, all pigs were harvested, carcass characteristics were determined, and back, belly, and jowl fat samples were collected for analysis. Overall (d 0 to 84), there were no differences among pigs fed the different fat sources for growth and carcass characteristics; however, pigs fed diets with added fat for the entire study had improved ( = 0.036) G:F compared with pigs fed the control diet without added fat. Pigs fed supplemental fat throughout the entire study also had improved ( < 0.05) ADG and G:F as well as heavier d-84 BW ( = 0.006) compared with pigs fed additional fat during only 1 period. Adding fat for the entire study increased ( = 0.032) backfat and tended to reduce ( = 0.079) the fat free lean index compared with pigs fed the control diet without added fat. Added fat also increased ( < 0.05) the iodine value (IV) when compared with pigs fed the control diet. Increasing the feeding duration of soybean oil lowered MUFA and increased PUFA concentrations for all fat depots, whereas these values remained relatively unchanged by the addition of tallow (duration × fat source interactions, < 0.05). Our study failed to show any feeding period × fat source interactions ( < 0.05) in fatty acid composition or IV for jowl fat, whereas this interaction occurred for belly fat and backfat, which would indicate a longer turnover rate for jowl fat. In conclusion, feeding additional fat improved ADG and G:F; however, feeding soybean oil for an increased duration, either alone or in combination with tallow, negatively affected the fatty acid composition and IV of different fat depots.

The inclusion of Duroc breed in maternal line affects pork quality and fatty acid profile

The aim of this study was to evaluate the effect of including different percentages of Duroc (D) breed in maternal line [Landrace (LR) × Large White (LW); LR × (LW × D); LR × D] and gender on meat quality and intramuscular (IMF) and subcutaneous (SCF) fatty acid composition. No significant differences were found among dam lines in ultimate pH, L* values and drip and cooking losses. There were higher percentages of saturated fatty acids in LR × D and LR × (LW × D) lines and higher percentages of polyunsaturated fatty acids in LR × LW line in IMF and SCF. Also, LR × D line produced pork with a lower Warner-Bratzler shear force values and higher IMF content and potential of lipid oxidation. Furthermore, the L*, a* and b* values and drip loss were greater in pork from entire males than females. The IMF and SCF of females were more monounsaturated and less polyunsaturated than those from entire males.

Effect of fatty acid composition and positional distribution within the triglyceride on selected physical properties of dry-cured ham subcutaneous fat

Analysis of fatty acid (FA) positional distribution within the triglyceride (TG) and selected physical properties of dry-cured ham subcutaneous fat (SF) were carried out. The slip point (SP) of the SF was related to the concentration and positional distribution of FA. When C16:0 was in Sn-2, the SP depended on the FA present in Sn-1,3. Hardness was related to the FA concentration in external positions of TG. A significant direct linear correlation between hardness against C18:0, SFA and average chain length (ACL) and inverse against C18:1, C18:2 and PUFA and unsaturation index (UI) in external positions was found. Adhesiveness was related to SFA, C16:0, C18:0, C18:1, MUFA, UI and ACL exclusively in Sn-2 position. A different role of FA in Sn-2 and Sn-1,3 positions on SP and texture properties of fat was found.

Effect of dietary conjugated linoleic acid supplementation on the technological quality of backfat of pigs

Pigs were fed diets containing 0, 0.25, 0.5 and 1% conjugated linoleic acid (CLA). Compared to controls, backfat from CLA fed pigs was firmer and extracted lipid contained increasing amounts of CLA, but a ±11% overall decrease in unsaturated fatty acids and a ±5% overall increase in each of C16:0 and C18:0 saturated fatty acids were noted. This resulted in a change in the melting properties of fat. The onset setting temperature increased from ±14°C to ±18°C for lipid of backfat of pigs from the 0.25 and 0.5% CLA supplementation groups, and to ±26°C for lipid from the 1% CLA supplementation group. The final melting temperatures increased from ±37°C to ±43°C and ±45°C, respectively. The presence of β'-crystals of C18:0-C16:0-C18:1c9 triacylglycerides in fat from CLA fed pigs and β-crystals in fat from 1% CLA fed pigs was observed. Fatty acid and melting point results explained the improvement in the technological quality of backfat as a result of dietary CLA supplementation.

Effect of pig breed and dietary protein level on selected fatty acids and stearoyl-coenzyme A desaturase protein expression in longissimus muscle and subcutaneous fat

The aims of the study were 1) to investigate effects of a low protein diet on fatty acids content and composition of the LM and subcutaneous adipose tissue in 3 genetically diverse breeds, Large White × Landrace, Alentejano, and Bizaro, and 2) to determine whether the effect of the low protein diet of fatty acid composition is associated with dietary modulation of stearoyl-CoA desaturase (SCD) protein expression. The experiments were conducted on 12 Large White × Landrace, 12 Alentejano, and 10 Bízaro female and male pigs. The average animal BW at the beginning of experiments was 40.8, 40.7, and 38.3 kg for Large White × Landrace, Alentejano, and Bízaro, respectively, and the BW of animals at slaughter was 90 kg. The diets contained 202 or 169 g/kg DM of CP (high and low protein diets, respectively) and were balanced in essential AA. The diets were fed until the animals reached 90 kg BW (approximately 73 d). It was established that Large White × Landrace pigs had a less (P = 0.001) total fatty acid content in subcutaneous adipose tissue when compared with Alentejano and Bízaro and less (P < 0.001) intramuscular fat (IMF) content when compared with Alentejano. There was a positive relationship between SCD protein expression in the LM and MUFA content (r = 0.627, P = 0.029) and SCD protein expression and total muscle fatty acids content (r = 0.725, P = 0.008) in Large White × Landrace but not in Alentejano and Bizaro breeds. It has been suggested that SCD protein expression is associated with regulation of fat deposition only in breeds with genetic predisposition to a low IMF content.