Effect of feeding system on the growth and carcass characteristics of Iberian pigs, and the use of ultrasound to estimate yields of joints

Use of Lupinus albus as a Local Protein Source in the Production of High-Quality Iberian Pig Products

The replacement of soybean meal with sweet white lupin (Lupinus albus L.) seeds was investigated in the diets of Iberian pigs during the growing and fattening phases, evaluating its effects on growth performance, carcass traits, and meat quality. Iberian pigs (n = 50) were divided into two dietary groups (n = 25 per group), receiving either a lupin-based concentrate or a soybean meal-based concentrate. The data were analysed using one-way analysis of variance (ANOVA), with a significance level of p < 0.05. The results showed that lupin substitution had no adverse effect on body weight, average daily gain, or carcass characteristics. No significant differences were observed in meat quality parameters such as pH, colour, and texture. However, significantly (p = 0.007) lower levels of saturated fatty acids (SFA) content were found in the intramuscular fat of pre-finishing (primor) pigs fed lupin-based diets. In addition, these pigs had lower plasma triglyceride levels at the end of the growing phase. Overall, the results suggest that sweet white lupin is a viable alternative protein source in Iberian pig production, offering potential health benefits in line with consumer preferences for sustainably produced, healthier meat products, without compromising production efficiency or product quality.

Effects of gender and diet on back fat and loin area ultrasound measurements during the growth and final stage of fattening in Iberian pigs

Abstract. Reared in extensive parcels, 50 castrated or spayed Iberian pigs were fattened with conventional or high-oleic-concentrate diets to evaluate the effect of diet and sex on the measurements of the loin area depth, back fat thickness and its layers during the last 6 months before slaughter at eight time points in two anatomical locations by serial scans. The scan was the factor that had the greatest influence, followed by sex and diet. Back fat thickness at 10th rib level was higher than at 14th rib level. The thickness of the outer, middle and inner layers progressively increased over the study period. Throughout the experimental period, the differences between two successive scans of the M. longissimus area did not differ significantly, obtaining the lowest value at the third scan and the highest at the fifth scan. The ultrasound back fat depth was affected by sex, being greater in females and in animals with a high-oleic diet. Positive significant correlations were observed for measurements assessed. The R2 values for the regression equations to estimate M. longissimus area were lower than the values found for the prediction of fat measurements, and they differed between sex and diet. The relative back fat growth was higher than M. longissimus area, not permitting the establishment of a similar growth pattern for fat and muscle. The sex and diet was taken into account in the predictive models. The subcutaneous adipose layers in Iberian pigs grow at different rates during the last 6 months before slaughter; with the ultrasound serial scan, it is possible to show these changes. The change in diet and the sex affect the adipose tissue development, being more noticeable in the middle layer of back fat at 10th rib level and the inner layer at 14th rib level. However, the sex and the use of an enriched oleic acid diet do not affect to loin development. As the middle layer of back fat shows more growth, this layer could be the best to be included in predictive models. The middle layer of back fat could also be good to be included in predictive models. Back fat thickness at the eighth scan can be predicted with moderate accuracy from corresponding measurements taken 30 days earlier and with less accuracy as the interval between measurements increases.

Effects of pork differentiation strategies in Canada on pig performance and carcass characteristics

Performance and quality traits were measured in carcasses from combinations of genotype, diet supplement, slaughter weight, and carcass chilling regime. Iberian-crossed pigs had lower live animal performance than Duroc and Lacombe. From 70 to 115 kg, Lacombe pigs grew slightly faster than Duroc. Duroc carcasses had a higher lean percentage, heavier ham and picnic primals, and lighter loins and bellies, compared with Lacombe and Iberian. Heavier carcasses had lower lean yield, except those from Iberian-crossed pigs, and bigger bellies. Meat from Duroc-crossed pigs was lighter in colour and higher in marbling, with intermediate values for fat hardness. Iberian carcasses displayed dark meat with intermediate marbling and the hardest fat. Meat from Lacombe pigs was the leanest although, like in all three breeds, marbling scores were higher in heavier carcasses. Generally, supplementing with canola and flax decreased and blast chilling increased fat hardness values. Dietary canola also seemed to affect meat colour traits, but these effects were not consistent among breeds and slaughter weights. The commercial combination of Duroc breed, control diet, and 115-kg slaughter weight showed a balance in terms of performance, carcass, and quality traits. Other combinations evaluated in this study showed potential to efficiently produce differentiated pork.

Feeding Iberian × Duroc cross pigs with crude glycerine: Effects of diet and gender on carcass and meat quality

Ninety (45 castrated males and 45 gilts) Iberian × Duroc pigs were used in this study. During the finishing period (95-160 kg body weight, 74 days) animals received conventional feed (control G0) or the same feed plus 5% (G5) or 10% (G10) of crude glycerine to partially replace wheat. In general, neither the diet nor gender affected ultrasound, carcass or meat quality parameters. The G10 had lower values of cooking loss and a* than the G5 and G0 groups. The fatty acids, C10:0, C12:0 and C18:3, in intramuscular fat were lower in both glycerine groups. Polyunsaturated fatty acids and 18:2 decreased and C20:0 increased at the subcutaneous fat of G10 animals. Castrated males produced carcasses with higher backfat thickness and fat content. Castrated males had a higher SFA content in subcutaneous fat than females (P<0.001). In conclusion, up to 10% crude glycerine could be used in the Iberian × Duroc diet.

Effect of sex and final fattening on ultrasound and carcass traits in Iberian pigs

A hundred and twenty-five castrated Iberian pigs (61 males and 64 females, from 106.9 kg of live weight at star to 160.3 kg at slaughter) was used to investigate the effect of feeding system on carcass attributes (backfat thickness and loin area measured with ultrasound before slaughter, and intramuscular fat and weights and yields of hams, forelegs and loins after slaughter). Pigs were fattened outdoor under extensive conditions. There were 4 treatments: "montanera", M; "recebo", R; "cebo a campo", C; and high oleic fed, O). Ultrasound images were collected at two rib locations (10th and 14th). M and O groups had the highest fat thickness and loin area was lower in M than in C group. M and O showed higher carcass weight and yield than the other groups. The largest ham weight was for C and the lowest for M groups. Loin weight and yield were higher in M and R than the other two groups (O and C).

Prediction of carcass composition, ham and foreleg weights, and lean meat yields of Iberian pigs using ultrasound measurements in live animals

The most valuable lean cuts from Iberian pigs are the hams, forelegs, and loins, which yield high quality cured meat products. This study aimed to assess the correlation between body composition measurements taken in vivo by ultrasonography in Iberian pigs and those taken on the carcass, which were then used to develop predictive models to estimate the weight and yield of these cuts. Before slaughter, 241 Iberian pigs were weighed (slaughter BW) and ultrasonically scanned. Ultrasound images were collected at 3 locations: the 10th intercostal space, caudal to the last rib to image the loin muscle, and the rear gluteal region [ultrasound gluteal backfat (u-GBF)]. After slaughter, the weight of the carcass (CW), ham (HW), foreleg (FW), and loin (LW) were determined, and the sum of these lean cuts weights (CLPW) and the corresponding yields were calculated. A portion of loin with the associated bones, backfat, and skin was obtained by cutting the carcass between the 10th and last ribs and was used to measure, at the 10th (10) and last (14) rib locations, the total backfat thickness, the area of the loin muscle (c-LA), and the thickness of the 4 backfat (BF) layers, namely, the outer (c-OBF), middle (c-MBF), outer plus middle (c-OMBF), and the inner (c-IBF). Finally, intramuscular fat percentages (IMF) were obtained from the meat samples. Corresponding measurements from the ultrasound (u) images were similarly taken at the same 2 ribs (u-BF, u-LA, u-OBF, u-MBF, u-OMBF, and u-IBF). The correlation was greatest between u-MBF10 and c-MBF10 (0.84). Most correlations between ultrasound and carcass measurements were lower at the last rib than at 10th rib. The greatest correlation of IMF10 occurred with u-IBF10 (0.40). Ham weight and HL were more correlated with u-BF10 than with u-BF14 whereas FW was more correlated with u-BF14. The u-LA was more correlated with HW, FW, and LW at the last rib than at the 10th rib. Slaughter live weight accounted for 0.84, 0.42, 0.36, and 0.54% of the variation for the prediction of CW, HW, FW, and CLPW, respectively. The u-LA10 and u-LA14 increased the variation explained by the model up to 0.89, 0.48, 0.39, and 0.62% for CW, HW, FW, and CLPW, respectively. Including u-GBF in the models also increased the R(2) values for predicting HW, LW, HY (ham yield), and LY (loin yield). In conclusion, u-LA10, u-LA14, and u-GBF may improve weight of commercial cuts and yield prediction in live Iberian pigs.

The prediction of ham composition by bioelectrical impedance analysis

The objective of this preliminary experiment was to study whether bioelectrical impedance analysis (BIA) can accurately predict the components of fresh pig hams. The trimmed right hams from 20 Iberian barrows were used. Six measures of resistance and reactance were taken by a bioelectrical impedance analyser. Simple and multiple regression equations were calculated for estimating bone, lean, intermuscular fat (IF), subcutaneous fat (SF), total fat (TF) and skin weights and percentages with respect to ham weight (HW). The HW accounted for 22% (P < 0.05) and 35% (P < 0.01) in the variations in lean and skin percentages, respectively. The ham compactness index (HCI), calculated as HW (in g)/(ham length, in cm)2, accounted for 20% (P < 0.05) and 38% (P < 0.01) in the variations in SF and TF percentages, respectively. The HW and BIA variables accounted for 60% (P < 0.001) of the variation in skin percentage; the HCI and BIA measures accounted for 79% (P < 0.0001), 66% (P < 0.001) and 78% (P < 0.0001) of the variation in lean, IF and SF percentages; and BIA variables accounted for 72% (P < 0.0001) of the variation in bone percentage. To determine the accuracy of the calculated regression equations, five additional trimmed fresh hams from Iberian barrows were used. Actual and predicted values were compared. The HW accurately predicted lean weight and skin percentage in linear regression equations, and HCI adequately predicted SF and TF weights in simple linear regression equations, and also SF percentage in inverse function. The additional inclusion of HW, HCI or BIA variables in the regression models did not improve the accuracy of the equations. It is concluded that BIA might be applied to predict the components of fresh hams but more studies are needed to determine whether levels of accuracy and precision are sufficient for this method to be used in practice.

Carcass Traits and Fatty Acid Composition of Subcutaneous, Intramuscular and Liver Fat from Iberian Pigs Fed in Confinement only with Acorns or a Formulated Diet

Twenty castrated male Iberian pigs were divided into two groups of 10 pigs each according to the experimental diet received daily during the fattening period in confinement (acorn fed ad libitum or 4 kg of a formulated diet rich in C18:1 n—9). Dietary effects on performance, carcass characteristics and backfat, intramuscular, and liver fatty acid composition were assessed. Pigs fed only with acorns ate less, leading to a lower growth performance and carcass quality than pigs fed the formulated diet. Pigs fed acorns had lower C16:0 proportions in outer, inner, and subinner subcutaneous backfat layers. The C18:1 n—9 proportions in the inner and subinner subcutaneous backfat layers were higher in pigs fed acorns than in those fed the formulated diet. Pigs fed acorns had higher C18:2 n—6 proportion than those fed the formulated diet in outer subcutaneous backfat layer. The diet did not affect outer, inner, and subinner subcutaneous backfat melting points. Except a higher C18:0 in intramuscular fat polar lipids and higher C16:1 n—9 in the liver polar lipid fraction in pigs fed acorns, the diet had no significant effect on intramuscular and liver fatty acid composition.