Chromium, CLA, and ractopamine for finishing pigs

Chromium Methionine and Ractopamine Supplementation in Summer Diets for Grower-Finisher Pigs Reared under Heat Stress

This study aimed to determine the effects of the dietary supplementation of chromium methionine (CrMet) and ractopamine (RAC) on pigs in the growing-finishing stage under heat stress. The parameters evaluated included productive behavior, blood components, carcass characteristics, organ weight, and meat quality. This study was conducted during the summer season in Sonora, Mexico. The treatments included: (1) control diet (CON), a base diet (BD) formulated to satisfy the nutritional requirements of pigs; (2) RAC, BD plus 10 ppm RAC supplemented during the last 34 days of the study; (3) CrMet-S, BD supplemented with 0.8 ppm of Cr from CrMet during the last 34 days; and (4) CrMet-L, BD supplemented with 0.8 ppm of Cr from CrMet for an 81 d period. RAC supplementation improved the productive behavior and main carcass characteristics of the pigs compared with CON. However, RAC and CrMet supplementation during the last 34 days showed similar results in terms of weight gain, carcass quality, blood components, organ weight, and meat quality. The addition of CrMet-S had a moderate (although not significant) increase in productive performance and carcass weight. These findings are encouraging, as they suggest that CrMet may be a potential alternative for growth promotion. However, more research is needed.

Meta-Analysis of the Effects of Organic Chromium Supplementation on the Growth Performance and Carcass Quality of Weaned and Growing-Finishing Pigs

Many factors influence the effects of exogenous organic chromium (EO-Cr) on the growth performance and carcass qualities of weaned and growing-finishing pigs, such as pig growth stages, types of EO-Cr, period of supplementation, and farm management. However, it is challenging to comprehensively consider all factors in one study. To solve this problem, we searched all relative literature published from 1 January 2000 to 1 January 2023, to systematically analyze and review the effects of EO-Cr on pig growth performance and carcass qualities via meta-analysis. Thirty-five papers were filtered and analyzed, which involved 4366 pigs. The results showed that, for weaned piglets, EO-Cr diets significantly increased the average daily gain (ADG, p < 0.001) and average daily feed intake (ADFI, p = 0.022) but reduced the feed-gain ratio (p = 0.004). In addition, for growing-finishing pigs, EO-Cr supplementation significantly increased the ADG (p < 0.001), carcass lean ratio (p = 0.020), and loin muscle area (p < 0.001), but had no significant effect on the ADFI (p = 0.071), feed-gain ratio (p = 0.692), dressing percent (p = 0.989), or back fat thickness (p = 0.142). Moreover, the effect of EO-Cr was greater in weaned piglets than in growing-finishing pigs. In terms of the dose effect of the supplement, chromium nicotinate is the most suitable EO-Cr type for weaned piglets with an optimal dosage range of 0.125-0.150 mg/kg. On the other hand, chromium picolinate is the most suitable EO-Cr type for growing-finishing pigs with an optimal dosage range of 0.250-0.300 mg/kg. In conclusion, EO-Cr supplementation is beneficial for enhancing the growth performance and carcass qualities of both weaned and growing-finishing pigs.

Effects of Organic Chromium Yeast on Performance, Meat Quality, and Serum Parameters of Grow-Finish Pigs

Trivalent chromium (Cr) is an essential trace element for humans and animals. This study was conducted to investigate the effects of chromium(III) yeast (CrYst) on growth performance, carcass characteristics, meat traits, antioxidant status, immune traits, and serum biochemical parameters of grow-finish pigs. A total of 72 commercial hybrid barrows (Duroc × Landrace × Large White) of approximately 50 kg body weight were allocated into two dietary treatments randomly, which received a corn-soybean meal basal diet or a basal diet supplemented with 100 mg CrYst/kg. The trial duration was 11 weeks divided into three periods from body weights of 50-75 kg, 75-100 kg, and 100-110 kg, respectively. The results revealed that supplemental CrYst did not affect growth performance. Organic CrYst supplementation significantly decreased the backfat depth and increased the meat tenderness score and juiciness score values in pigs (P < 0.05), while other carcass traits and meat traits indexes were unaffected. CrYst addition significantly decreased serum malondialdehyde (MDA) content of pigs in the whole growth phase; significantly increased the serum levels of immunoglobulin G (IgG), total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-Px), and reduced glutathione (GSH) in growing pigs; and also increased the serum IgG, IgM, and GSH concentrations in pigs during the finishing phase (P < 0.05). Additionally, diets supplemented with CrYst significantly decreased the serum high-density lipoprotein cholesterol (HDL-C) content in growing pigs and significantly increased the serum LDL-C level at the fattening period (P < 0.05), whereas no significant differences were observed for the other serum biochemical indexes compared to the control pigs. In conclusion, CrYst supplementation could reduce lipid peroxidation and backfat thickness and improve the meat tenderness and juiciness, immune traits, and antioxidant status of pigs.

Performance, Carcass Traits, Pork Quality and Expression of Genes Related to Intramuscular Fat Metabolism of Two Diverse Genetic Lines of Pigs

We aimed to evaluate the performance, carcass and pork quality traits, as well as the mRNA expression of genes related to intramuscular fat deposition in female pigs from different genetic lines. A total of eighteen female pigs (Large White × Landrace × Duroc × Pietrain) × (Large White × Landrace) (Hybrid) averaging 88.96 ± 3.44 kg in body weight and twelve female pigs (Duroc) × (Large White × Landrace) (Duroc) averaging 85.63 ± 1.55 kg in body weight were assigned to a completely randomized design experimental trial that lasted 45 days. Pigs from both genetic lines received the same diet, which was initially adjusted for their nutritional requirements from 0 to 17 days of age and subsequently adjusted for nutritional requirements from 17 to 45 days of age. The performance of pigs did not differ among groups (p > 0.05). Duroc pigs showed a lower backfat thickness (p < 0.03) and greater intramuscular fat content (p < 0.1). A greater mRNA expression of the peroxisome proliferator-activated receptor gamma gene (PPARγ, p = 0.008) and fatty acid protein translocase/cluster differentiation (FAT/CD36, p = 0.002) was observed in the Longissimus dorsi muscle of Duroc pigs. Similarly, a greater expression of PPARγ (p = 0.009) and FAT/CD36 (p = 0.02) was observed in the Soleus muscle of Duroc pigs. Overall, we observed that despite the lack of differences in performance between the genetic groups, Duroc pigs had greater intramuscular fat content than hybrid pigs. The increased intramuscular fat content was associated with an increase in the mRNA expression of key transcriptional factors and genes encoding enzymes involved in adipogenesis and lipogenesis in glycolytic and oxidative skeletal muscle tissues.

Effects of dietary chromium propionate and space allowance on performance and carcass responses of growing-finishing pigs

In a 72-d trial, 256 pigs (Line 600 × 241, DNA Columbus, NE) were used to determine the effect of dietary Cr (Cr propionate; Kemin Industries, Des Moines, IA) and physical space restriction on performance and carcass characteristics of finishing pigs. Pens were blocked by initial weight and randomly assigned to treatments with eight pigs per pen and eight pens per treatment. Treatments were arranged in a 2 × 2 factorial with main effects of Cr (control and Cr propionate, 200 µg/kg added Cr) and space allowances (0.91 m²/animal: normal and 0.63 m²/animal: restricted). Pigs were fed in three dietary phases and pigs were weighed approximately every 14 d throughout the study. Feed efficiency was calculated as both a standard gain to feed ratio and as an adjusted G:F ratio at a common final bodyweight. There were no evidence of space allocation × Cr interactions for any measured responses (P > 0.05). Space restriction decreased (P < 0.001) daily weight gain, final body weight, hot carcass weight, and daily feed intake, but increased carcass yield (P = 0.009) and decreased backfat depth (P = 0.003). Feed efficiency was greater for pigs provided a normal space allowance when adjusted for a common final bodyweight (P = 0.021), although no evidence of a difference was observed for unadjusted G:F (P = 0.687). Adding Cr to the diet reduced G:F on both an adjusted and unadjusted basis (P ≤ 0.021). There was marginally significant evidence that pigs provided Cr had lower average daily gain (P = 0.079) and final bodyweight (P = 0.056) compared to pigs not provided added Cr. There was marginally significant evidence that Cr resulted in greater backfat depth (P = 0.069), although no evidence of a difference in other carcass parameters were observed (P > 0.10). These results demonstrated that there were no interactions between Cr propionate and space allocation, illustrating that under the conditions of this study Cr propionate did not provide an advantage in growth performance or carcass characteristics in either adequate or restricted space allocation.

Overall assessment of antibiotic substitutes for pigs: a set of meta-analyses

Background

Antibiotic growth promoters are widely used to improve weight gain. However, the abuse of antibiotics can have many negative effects on people. Developing alternatives to antibiotics is an urgent need in livestock production. We aimed to perform a meta-analysis and network meta-analysis (NMA) to investigate the effects of feed additives as potential antibiotic substitutes (ASs) on bacteriostasis, growth performance, intestinal morphology and immunity. Furthermore, the primary, secondary, and tertiary ASs were defined by comparing their results with the results of antibiotics.

Results

Among 16,309 identified studies, 37 were summarized to study the bacteriostasis effects of feed additives, and 89 were included in the meta-analysis and NMA (10,228 pigs). We summarized 268 associations of 57 interventions with 32 bacteria. The order of bacteriostasis effects was as follows: antimicrobial peptides (AMPs) ≈ antibiotics>organic acids>plant extracts>oligosaccharides. We detected associations of 11 feed additives and 11 outcomes. Compared with a basal diet, plant extract, AMPs, probiotics, microelements, organic acids, bacteriophages, lysozyme, zymin, and oligosaccharides significantly improved growth performance (P < 0.05); organic acids, probiotics, microelements, lysozyme, and AMPs remarkably increased the villus height:crypt depth ratio (V/C) (P < 0.05); and plant extracts, zymin, microelements, probiotics, and organic acids notably improved immunity (P < 0.05). The optimal AMP, bacteriophage, lysozyme, microelements, oligosaccharides, organic acids, plants, plant extracts, probiotics, and zymin doses were 0.100%, 0.150%, 0.012%, 0.010%, 0.050%, 0.750%, 0.20%, 0.040%, 0.180%, and 0.100%, respectively. Compared with antibiotics, all investigated feed additives exhibited no significant difference in effects on growth performance, IgG, and diarrhoea index/rate (P > 0.05); AMPs and microelements significantly increased V/C (P < 0.05); and zymin significantly improved lymphocyte levels (P < 0.05). Furthermore, linear weighting sum models were used to comprehensively estimate the overall impact of each feed additive on pig growth and health.

Conclusions

Our findings suggest that AMPs and plant extracts can be used as primary ASs for weaned piglets and growing pigs, respectively. Bacteriophages, zymin, plants, probiotics, oligosaccharides, lysozyme, and microelements can be regarded as secondary ASs. Nucleotides and organic acids can be considered as tertiary ASs. Future studies should further assess the alternative effects of combinational feed additives.

Effect of ractopamine and conjugated linoleic acid on performance of late finishing pigs

The dietary inclusion of feed additives to improve the carcass characteristics of the final product is of great importance for the pork production chain. The aim of our study was to evaluate the effects of the association of ractopamine (RAC) and conjugated linoleic acid (CLA) on the performance traits of finishing pigs during the last 26 days prior to slaughter. In total, 810 commercial hybrid barrows were used. Animals were distributed among treatments according to a randomised block design in a 3 × 3 factorial arrangement, with three RAC levels (0, 5 or 10 ppm) and three CLA levels (0, 0.3 or 0.6%). Pigs fed the diet with 5 ppm RAC had higher average daily feed intake (ADFI) (2.83 kg; P < 0.05) when compared with those fed 10 ppm RAC and the control diet (2.75 and 2.74 kg, respectively). Lower ADFI values (P < 0.01) were observed with the diets containing CLA compared with the control diet with no CLA (2.73 and 2.75 v. 2.85 kg/day, respectively). The average daily weight gain of pigs fed 5 and 10 ppm RAC was +148 and +173 g/dayhigher (P < 0.001), respectively, than those fed the control diet. Dietary RAC levels influenced (P < 0.001) feed conversion ratio (FCR), which was reduced as RAC levels increased, with the pigs fed 10, 5 and 0 ppm RAC presenting FCR values of 2.57, 2.71 and 3.05, respectively. FCR also improved (P < 0.05) with the inclusion of 0.6% CLA relative to the control diet (2.70 v. 2.84, respectively). There was a significant interaction between CLA × RAC levels (P < 0.01) for final BW, loin eye area (LEA) (P < 0.05) and backfat thickness (BT) (P < 0.05). The treatments containing 10 ppm RAC + 0.6% or 0.3% CLA increased LEA and reduced BT. In conclusion, the level of 10 ppm inclusion of RAC increased the overall performance parameters of pigs and therefore improved production efficiency. The combined use of RAC and CLA promoted a lower feed conversion ratio as well as better quantitative carcass traits, as demonstrated by the higher LEA and lower BT. The dietary inclusion of CLA at 0.3% improved feed efficiency, however, without affecting LEA or BT yields.

Reproducible Molecularly Imprinted Piezoelectric Sensor for Accurate and Sensitive Detection of Ractopamine in Swine and Feed Products

This paper describes the development of a reproducible molecularly imprinted piezoelectric sensor for the accurate and sensitive detection of ractopamine (RAC) in swine and feed products. The synthesized molecularly imprinted polymer (MIP) was directly immobilized on the surface of a quartz crystal microbalance (QCM) Au chip as the recognition element. The experimental parameters in the fabrication, measurement and regeneration process were evaluated in detail to produce an MIP-based piezoelectric sensor with high sensing capability. The developed piezoelectric sensor was verified to perform favorably in the RAC analysis of swine and feed products, with acceptable accuracy (recovery: 75.9⁻93.3%), precision [relative standard deviation (n = 3): 2.3⁻6.4%], and sensitivity [limit of detection: 0.46 ng g-1 (swine) and 0.38 ng g-1 (feed)]. This portable MIP-based chip for the piezoelectric sensing of RAC could be reused for at least 30 cycles and easily stored for a long time. These results demonstrated that the developed MIP-based piezoelectric sensor presents an accurate, sensitive and cost-effective method for the quantitative detection of RAC in complex samples. This research offers a promising strategy for the development of novel effective devices used for use in food safety analysis.