Dietary isoleucine supplementation enhances growth performance, modulates the expression of genes related to amino acid transporters and protein metabolism, and gut microbiota in yellow-feathered chickens

This study investigated the effects of dietary isoleucine (Ile) on growth performance, intestinal expression of amino acid transporters, protein metabolism-related genes and intestinal microbiota in starter phase Chinese yellow-feathered chickens. Female Xinguang yellow-feathered chickens (n = 1,080, aged 1 d) were randomly distributed to 6 treatments, each with 6 replicates of 30 birds. Chickens were fed diets with 6 levels of total Ile (6.8, 7.6, 8.4, 9.2, 10.0, and 10.8 g/kg) for 30 d. The average daily gain and feed conversion ratio were improved with dietary Ile levels (P < 0.05). Plasma uric acid content and glutamic-oxalacetic transaminase activity were linearly and quadratically decreased with increasing dietary Ile inclusion (P < 0.05). Dietary Ile level had a linear (P < 0.05) or quadratic (P < 0.05) effect on the jejunal expression of ribosomal protein S6 kinase B1 and eukaryotic translation initiation factor 4E binding protein 1. The relative expression of jejunal 20S proteasome subunit C2 and ileal muscle ring finger-containing protein 1 decreased linearly (P < 0.05) and quadratically (P < 0.05) with increasing dietary Ile levels. Dietary Ile level had a linear (P = 0.069) or quadratic (P < 0.05) effect on the gene expression of solute carrier family 15 member 1 in jejunum and solute carrier family 7 member 1 in ileum. In addition, bacterial 16S rDNA full-length sequencing showed that dietary Ile increased the cecal abundances of the Firmicutes phylum, and Blautia, Lactobacillus, and unclassified_Lachnospiraceae genera, while decreased that of Proteobacteria, Alistipes, and Shigella. Dietary Ile levels affected growth performance and modulated gut microbiota in yellow-feathered chickens. The appropriate level of dietary Ile can upregulate the expression of intestinal protein synthesis-related protein kinase genes and concomitantly inhibit the expression of proteolysis-related cathepsin genes.

POS1190 IMPACT OF COVID-19 PANDEMIC ON PATIENTS WITH RHEUMATIC AND MUSCULOSKELETAL DISEASES: DISRUPTIONS IN CARE AND SELF-REPORTED OUTCOMES

Background

The COVID-19 pandemic represents a challenge to the care of patients with rheumatic and musculoskeletal diseases (RMDs).

Objectives

This study aimed to evaluate the impact of the pandemic on the care of RMD patients, their health and wellbeing.

Methods

This cross-sectional study involved 120 RMDs patients at the rheumatology department at Suez Canal University Hospital in Ismailia, Egypt. Patients were interviewed for sociodemographic and disease-related history. Further assessments were performed using Kessler 6-items (1), Fear of COVID-19 scale (2), and COVID-19–Impact on Quality-of-Life scale (3).

Results

Patients with rheumatoid arthritis and systemic lupus erythematosus made up most of our sample (72.5%, 19.2% respectively). About 50% of patients were experiencing limitation in the access to rheumatologic care, and a similar percentage had changed or discontinued their medications. DMARDs shortage and concerns about the increased risk of COVID-19 infection because of immunosuppressive drugs were the most frequently reported reasons for non-adherence to medication. The percentage of patients with uncontrolled disease had significantly increased from 8.3% prior to the COVID-19 pandemic to 20% during the pandemic. Patients perceived their overall quality of life as average (4.93 on a rating scale from 0 to 10). The Fear of COVID-19 score ranged from 7 to 35 with a mean of 26 (±7.6), while the COV19–Impact on Quality of Life score ranged from 6 to 30 points with a mean of 22.6 (±6.7). About 60% of patients reported a high level of psychological distress.

Conclusion

The pandemic negatively influenced the mental health, quality of life, adherence to medications, access to rheumatology care, and disease control of RMDs patients.

References

[1]Kessler RC, Andrews G, Colpe LJ, Hiripi E, Mroczek DK, Normand SL, Walters EE, Zaslavsky AM. Short screening scales to monitor population prevalences and trends in non-specific psychological distress. Psychological medicine. 2002 Aug;32(6):959-76.

[2]Ahorsu DK, Lin CY, Imani V, Saffari M, Griffiths MD, Pakpour AH. The Fear of COVID-19 Scale: Development and Initial Validation. Int J Ment Health Addict 2020;1-9. doi:10.1007/s11469-020-00270-8.

[3]Repišti S, Jovanović N, Kuzman MR, Medved S, Jerotić S, Ribić E, Majstorović T, Simoska SM, Novotni L, Milutinović M, Stoilkovska BB. How to measure the impact of the COVID-19 pandemic on quality of life: COV19-QoL–the development, reliability and validity of a new scale. Global Psychiatry 2020, 3(2), 2020, 201-10. doi: 10.2478/gp-2020-0016.

Disclosure of Interests

None declared

Effects of maternal and progeny dietary selenium supplementation on growth performance and antioxidant capacity in ducklings

This study evaluated the effects of selenium (Se) supplementation in maternal and offspring diets on performance and antioxidant capacity of ducklings aged from 0 to 2 wk. A total of 144 female Longyan duck breeders aged 22-wk were allotted into 2 treatments and fed a control diet or a 0.16 mg Se/kg supplemented diet. At 40-wk, 120 offspring from each treatment were divided into 2 groups, with 6 replicates of 10 birds. Using a 2 × 2 factorial design, ducklings from each maternal dietary treatment were assigned to a control diet or a 0.16 mg Se/kg supplemented diet from hatch to 2-wk. Compared with Se-deficient diet, maternal diet supplemented with 0.16 mg Se/kg increased the BW of hatchlings (P < 0.01). There were interactions between maternal and progeny diet with 0.16 mg Se/kg in BW of ducklings aged 2 wk and BW gain (BWG) as ducklings from maternal Se/progeny none treatment had the lightest BW and BWG (P < 0.01). Maternal diet with 0.16 mg Se/kg decreased plasma concentration of uric acid and insulin-like growth factor 1 (P < 0.01), and progeny diet supplemented with 0.16 mg Se/kg increased the activities of glutathione peroxidase 3 (GPx3) in plasma and glutathione peroxidase 1 in erythrocyte (P < 0.01). Maternal diet with 0.16 mg Se/kg increased (P < 0.05) the hepatic activity of total superoxide dismutase (T-SOD). Progeny diet supplemented with 0.16 mg Se/kg increased (P < 0.01) hepatic activity of GPx3 and decreased (P < 0.01) the hepatic concentration of malondialdehyde. Interactions were detected between maternal and progeny diet with 0.16 mg Se/kg in hepatic activity of T-SOD and maternal and progeny diet supplemented with Se displayed the highest hepatic activity of T-SOD (P < 0.05). Overall, Se supplementation in the diet of duck breeders and offspring increased the antioxidant capacity of ducklings. Maternal Se supplementation increased the BW of hatchlings, whereas maternal and progeny dietary Se supplementation did not affect the BWG of ducklings aged from 0 to 2 wk. Se supplementation with additional 0.16 mg/kg in the diet of duck breeders and offspring displayed beneficial effects particularly on the antioxidant capacity in ducklings.

PSVIII-7 Dietary L-arginine supplementation enhances growth performance, intestinal antioxidant capacity, immunity and modulate gut microbiota in yellow feathered chickens

This study investigated the effects of dietary Arginine (Arg) on performance, intestinal antioxidant capacity, immunity, and gut microbiota in Chinese yellow-feathered chickens. One thousand and two hundred 1-day-old female Qingyuan partridge chickens were randomly assigned to 5 groups with 6 replicates of 40 birds each. Chickens were fed diets with 5 total Arg levels (8.5, 9.7, 10.9, 12.1 and 13.3 g/kg) without antibiotics for 30 D. Average daily feed intake, average daily gain, and feed conversion ratio were improved with dietary Arg levels (P &lt; 0.05). Dietary Arg level had a linear (P &lt; 0.05) or quadratic (P &lt; 0.05) effect on the gene expression of glutathione peroxidase 1, hame oxygenase 1, nuclear factor erythroid 2, linearly and quadraticly increased activities of GSH-Px and total antioxidant capacity in the jejunum and ileum. In addition, relative expression of interleukin-1β and toll-like receptor 4 decreased linearly (P &lt; 0.05) and quadratically (P &lt; 0.05) in the ileum with increasing dietary Arg levels; secretory immunoglobulin A contents were increased. In addition, sequencing data of 16S rRNA indicated that dietary Arg increased the abundances of Firmicutes phylum, Romboutsia and Candidatus Arthromitus genus, while decreased that of Clostridium sensu stricto 1. A diet containing 12.1 g Arg/kg could promote growth performance, intestinal antioxidation, innate immunity and modulate gut microbiota in yellow feathered chickens.

Dietary L-arginine supplementation enhances growth performance, intestinal antioxidative capacity, immunity and modulates gut microbiota in yellow-feathered chickens

This study investigated the effects of dietary Arginine (Arg) on performance, intestinal antioxidative capacity, immunity, and gut microbiota in Chinese yellow-feathered chickens. One thousand two hundred 1-day-old female Qingyuan partridge chickens were randomly assigned to 5 groups with 6 replicates of 40 birds each. Chickens were fed diets with 5 levels of total Arg (8.5, 9.7, 10.9, 12.1, and 13.3 g/kg) without antibiotics for 30 d. The ADFI, ADG, and feed conversion ratio were improved with dietary Arg levels (P < 0.05). The proportions of CD3⁺ and CD4⁺/CD8⁺ lymphocytes responded in a linear (P < 0.05) manner and those of CD4⁺ in a linear or quadratic (P < 0.05) manner as dietary Arg levels increased. Dietary Arg level had a linear (P < 0.05) or quadratic (P < 0.05) effect on the gene expression of glutathione peroxidase 1, heme oxygenase 1, nuclear factor erythroid 2-related factor 2, and the activities of glutathione peroxidase and total antioxidative capacity in the jejunum and ileum. The relative expression of IL-1β, myeloid differentiation primary response 88, and Toll-like receptor 4 decreased linearly (P < 0.05) in the ileum with increasing dietary Arg levels; secretory IgA contents were increased. In addition, sequencing data of 16S rRNA indicated that dietary Arg increased the relative abundance of Firmicutes phylum, Romboutsia and Candidatus Arthromitus genera, while decreased that of Clostridium sensu stricto 1. A diet containing 12.1 g Arg/kg promoted growth performance, intestinal antioxidation, and innate immunity and modulated gut microbiota in yellow-feathered chickens.

AB1238 THE ARABIC LUPUSPRO: CROSS-CULTURAL VALIDATION OF A DISEASE-SPECIFIC PATIENT-REPORTED OUTCOME TOOL FOR QUALITY OF LIFE IN LUPUS PATIENTS

Background:

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with high morbidity and disability that affects all aspects of quality of life (QoL).(1)LupusPRO is a disease-targeted patient-reported outcome tool for the measurement of health and non-health related quality of life (HRQoL and Non-HRQoL) in SLE patients.(2)

Objectives:

To translate, cross-culturally adapt, and validate the LupusPRO v.1.8 into the Arabic Language.

Methods:

LupusPRO v.1.8 was translated into Arabic following the forward-backward translation guideline.(3)The Arabic version of LupusPRO was subsequently applied to 107 Egyptian SLE patients. To assess test-retest reliability, the Arabic LupusPRO was completed on two occasions, two weeks apart. Validation was performed against the Arabic version of Medical Outcomes Study Short Form (SF-36), the Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI) and the Systemic Lupus International Collaborating Clinics/American College of Rheumatology damage index (SDI). Discriminant validity of Arabic LupusPRO was evaluated against the SF-36 (item 1), while the conceptual framework was evaluated by the confirmatory factor analysis (CFA).

Results:

The study included 107 patients, 95% of whom were women. Their median age was 32 (range:18-55) years. Arabic LupusPRO’s Cronbach’s alpha ranged from 0.71 to 0.98 except for the social support domain (0.65). Test-retest reliability ranged from 0.83 to 0.98. Convergent validity with corresponding domains of the SF-36 was satisfactory. Criterion validity showed a weak and non-significant correlation of lupusPRO domains with SDI except for physical domain and significant weak correlation with SELENA-SLEDAI (Table1). Discriminant validity showed acceptable results against the SF-36 (item 1). The CFA showed good model fit indices for the hypothesized item-to-scale relationships (CFI =0.988, TLI = 0.987, and RMSEA=0.062), with most of item-to-scale loadings greater than 0.9.

Conclusion:

The Arabic version of LupusPRO v1.8 is a reliable and valid tool for measuring QoL(HRQoL and Non-HRQoL) in Arabic-speaking SLE patients.

References:

[1]Mcelhone K, Abbott J, Teh L-SJL. A review of health- related quality of life in systemic lupus erythematosus. Lupus 2006;15(10):633-43.

[2]Jolly M, Pickard AS, Block JA, et al. Disease-specific patient reported outcome tools for systemic lupus erythematosus. Semin Arthritis Rheum. 2012;42(1):56–65.

[3]Beaton D, Bombardier C, Guillemin F, Ferraz M. Guidelines for the Process of Cross-Cultural Adaption of Self-Report Measures. Spine. 2001;25:3186-91.

Table 1.

Validity of the Arabic LupusPRO against disease activity, damage index and SF-36

LupusPRO DomainValiditySF-36Total SLEDAITotal SDIDomainRho (P)Rho (P)Rho (P)Lupus Symptoms-0.25 (0.010)-0.17 (0.08)Cognition-0.15 (0.117)-0.21 (0.03)Lupus Medications-0.22 (0.021)-0.37 (0.001)Procreation0.003 (0.977)-0.20 (0.04)Physical HealthRF0.84 (<0.001)-0.34 (<0.001)-0.31 (0.001)RP0.75 (<0.001)Sleep-0.32 (0.001)-0.09 (0.33)FatigueVT0.80 (<0.001)-0.33 (0.001)-0.12 (0.33)PainBP0.86 (<0.001)-0.22 (0.026)-0.18 (0.07)Emotional HealthMH0.74 (<0.001)-0.33 (0.001)-0.19 (0.05)RE0.80 (<0.001)Body Image-0.30 (0.002)-0.25 (0.008)Desire/Goals-0.28 (0.004)-0.10 (0.30)Social Support0.22 (0.02)-0.20 (0.04)Coping0.07 (0.461)-0.20 (0.03)Satisfaction of Medical Care0.18 (0.066)-0.11 (0.24)HRQoLGH0.81 (<0.001)-0.37 (<0.001)-0.28 (0.004)None-HRQoL-0.08 (0.42)-0.26 (0.007)

PF: Physical functioning; RP: role physical; RE: role emotional; VT: vitality; MH: Mental health; BP: Bodily Pain; GH: General health.

Disclosure of Interests:

None declared

The effects of dietary Se on productive and reproductive performance, tibial quality, and antioxidant capacity in laying duck breeders

This study evaluated the optimal concentrations of dietary Se for the productive and reproductive performance, tibial quality, and antioxidant status in duck breeders aged 23 to 49 wk. In total, 432 Longyan duck breeders aged 22 wk were allotted randomly to 6 treatments, each with 6 replicates of 12 individually caged birds. The experiment lasted for 27 wk, and birds were fed corn-soybean meal-based diets containing 0.11, 0.19, 0.27, 0.35, 0.43, or 0.51 mg Se/kg, respectively. The tested dietary Se levels did not affect egg production and tibial quality of duck breeders. The Se contents of the shell, yolk or albumin, whole egg, and the fertility of set eggs increased in a linear and quadratic manner (P < 0.05) in response to the increased dietary Se level, whereas the yolk malondialdehyde (MDA) and embryonic mortality decreased. The activities of glutathione peroxidase 3 (Gpx3) in plasma and Gpx1 in the erythrocytes and livers of breeder ducks increased in a linear and quadratic manner (P < 0.05) in response to increased dietary Se levels, whereas the total superoxide dismutase (T-SOD) activity increased and the MDA concentration decreased in the liver. The activity of Gpx3 in the plasma and Gpx1 in the erythrocytes and livers of newly hatched ducklings increased linearly (P < 0.01) with the increase in Se level, whereas the T-SOD activity and MDA concentration did not change. In conclusion, diets containing 0.27 mg Se/kg led to the highest egg fertility and hatchability in Longyan duck breeders, and using levels >0.19 mg Se/kg diet enhanced the antioxidant capacity in breeders and their offspring. The regression model indicated that dietary Se levels 0.19, 0.27, 0.28, 0.24, and 0.30 mg/kg are optimal levels to obtain maximum Se deposition efficiency in eggs, egg fertility, Gpx1 activity in erythrocytes and liver in duck breeders, and plasma activity of Gpx3 in newly hatched ducklings, respectively.

Research Note: Effects of riboflavin on reproductive performance and antioxidant status of duck breeders

An experiment was conducted to investigate the effects of dietary riboflavin levels on reproductive performance, riboflavin status, and antioxidant status of laying duck breeders, to estimate the requirement of this vitamin for duck breeders. Different levels crystalline riboflavin (0, 2.5, 5, 10, and 15 mg/kg) were supplemented to a corn-soybean-corn gluten meal basal diet to produce 5 dietary treatments with different analyzed total riboflavin levels (1.48, 3.20, 6.30, 11.71, and 16.83 mg/kg). A total of 80 White Pekin duck breeders aged 40 wk were allotted to 5 dietary treatments of 16 birds each (8 replicates per treatment and 2 breeders per replicate), and all birds were raised individually for 9 wk. At the end of the experiment, reproductive performance, tissue riboflavin concentrations, and antioxidant status of White Pekin duck breeders were measured. The results showed that body weight, egg weight, egg production, and egg fertility were not affected by dietary riboflavin levels. However, among all of the laying duck breeders, the birds fed the basal diet without riboflavin supplementation had the lowest egg hatchability, plasma riboflavin, egg yolk riboflavin, and egg albumen riboflavin (P < 0.001). In addition, the duck breeders fed the basal diet without riboflavin supplementation showed the lowest antioxidant capacity indicated by greatest plasma malondialdehyde (MDA) content and lowest reduced glutathione content, total superoxide dismutase (T-SOD) activities, and total antioxidant capacity in both plasma (P < 0.001) and egg yolk (P < 0.001). These results revealed that dietary riboflavin supplementation improved the reproductive performance and antioxidant status of the duck breeders. According to the broken-line model, the riboflavin requirements (based on dietary total riboflavin) of laying duck breeders in terms of the egg hatchability, plasma riboflavin, egg yolk riboflavin, egg albumen riboflavin, plasma T-SOD activity, and plasma MDA content were 3.19, 7.42, 3.88, 7.44, 6.45, and 8.84 mg/kg, respectively.

Effects of dietary lysine on productivity, reproductive performance, protein and lipid metabolism-related gene expression in laying duck breeders

This study investigated whether dietary lysine (Lys) affects productive performance and expression of genes related to protein and lipid metabolism in laying duck breeders. Longyan duck breeders (n = 540, 19 wk of age) were randomly assigned to 6 groups with 6 replicates of 15 birds each. Breeders were fed diets with 6 total Lys levels (6.4, 7.2, 8.0, 8.8, 9.6, and 10.4 g/kg) for 26 wk duration. Egg production, egg weight, egg mass, feed conversion ratio, hatchability, hatchling weight, albumen weight, eggshell weight, yolk weight, and yolk proportion increased with dietary Lys levels (P < 0.05). Dietary Lys level had a linear (P < 0.05) and quadratic (P < 0.05) effects on maternal hepatic expression of mechanistic target of rapamycin, eukaryotic translation initiation factor 4E binding protein 1, ubiquitin conjugating enzyme E2K (UBE2K), cathepsin B (CTSB), and quadratically (P < 0.05) increased the concentrations of plasma Lys, leucine, threonine, and tryptophan in duck breeders. In contrast, maternal dietary Lys suppressed expression of proteasome 26S subunit, UBE2K, and CTSB in the liver of hatchlings. Moreover, relative expression of peroxisome proliferator-activated receptors alpha, carnitine palmitoyltransferase 1A, and very low density apolipoprotein-II increased linearly (P < 0.05) and quadratically (P < 0.05), and that of VLDL receptor (VLDLR) decreased quadratically (P < 0.05) in the liver of duck breeders with increasing dietary Lys levels; hepatic triglyceride and cholesterol contents were reduced. Maternal dietary Lys suppressed hepatic expression of VLDLR in the hatchlings. A diet containing 8.6 g Lys/kg promoted protein turnover and lipid metabolism in laying duck breeders, which positively reflected in the productivity and reproductive performance.

Dietary curcumin enhances intestinal antioxidant capacity in ducklings via altering gene expression of antioxidant and key detoxification enzymes

The study investigated the effects of dietary curcumin supplementation on tissue distribution of curcumin and its metabolites, intestinal antioxidant capacity, and expression of detoxification-related genes in ducks. A total of 720 one-day-old male Cherry Valley Pekin ducklings (initial BW 58.6 ± 0.1 g) were randomly assigned to 4 dietary groups each with 6 replicates of 30 ducks using a single factorial arrangement design. Ducks in the control group were fed a basal diet and the remainder were fed the basal diet supplemented with 200, 400, or 800 mg/kg curcumin. The experiment lasted for 21 D. Curcumin was present at 13.12 to 16.18 mg/g in the cecal digesta, 75.50 to 575.40 μg/g in jejunal mucosa, 35.10 to 73.65 μg/g in liver, and 7.02 to 7.88 μg/mL in plasma. The jejunal and hepatic contents of curcumin increased significantly (P < 0.05) in response to supplementation with 400 and 800 mg/kg of curcumin respectively, compared with 200 mg curcumin/kg group. There was a linear (P < 0.001) effect of dietary curcumin on relative abundance of SOD1, GPX1, CAT, HO-1, and Nrf2 transcripts, and a quadratic (P < 0.001) increase in the activities of GSH-Px and T-AOC in jejunal mucosa. The expression of CYP1A4, CYP2D17 increased and CYP1B1, CYP2A6 decreased linearly (P < 0.001) with dietary curcumin concentrations. In addition, dietary curcumin increased gene expression of GST, MRP6, and ABCB1 in jejunal mucosa. In conclusion, dietary supplementation with 200 to 800 mg/kg curcumin enhanced the accumulation of curcumin and its metabolites in jejunum as well as increasing the antioxidant capacity and detoxification potential, which play major roles in the protection of duck intestines against damage.

Effects of corn dried distillers' grains with solubles on performance, egg quality, yolk fatty acid composition and oxidative status in laying ducks

The study investigated the effects of increasing content of corn distillers' dried grains with solubles (DDGS) in the diets of laying ducks on oxidative status, laying performance, egg quality, and egg yolk fatty acid composition. Longyan females (1080) with similar BW at 17 wk of age were randomly assigned to 6 treatment groups, each consisting of 6 replicates of 30 birds. The basal diet (I) was a typical corn-soybean ration while the experimental diets (II to VI) substituted corn DDGS for soybean meal and wheat bran and a small reduction of corn. The level of substitution in diets (II to VI) was 6%, 12%, 18%, 24% and 30%. The experiment lasted for 18 wk. Average egg weight decreased linearly as the level of corn DDGS inclusion increased (P < 0.001). Haugh unit, albumen weight, and proportion declined as linear responses to corn DDGS substitution (P < 0.05), but yolk color linearly increased (P < 0.001); the proportions of oleic (C18:1) and total monounsaturated fatty acids in egg yolk linearly decreased with increasing corn DDGS and many of the key polyunsaturated fatty acids (PUFAs) like linoleic (C18:2n-6), arachidonic (C20:4n-6) and α-linolenic (C18:3n-3) acids linearly increased (P < 0.001), but not those of eicosapentaenoic (C20:5n-3) and docoshexaenoic (C22:6n-3) acids. The PUFAs n-6/n-3 ratio linearly increased with increasing corn DDGS level (P < 0.001). Increasing corn DDGS linearly increased hepatic expression of GPX1, HO-1, and Nrf2 and hepatic activity of GSH-Px and the liver content of MDA (P < 0.001). There were no treatment effects on egg production, egg mass, feed conversion ratio, eggshell thickness, strength, and yolk cholesterol content (P > 0.05). In conclusion, the current study indicates that the use of corn DDGS is possible as a replacement, primarily for soybean meal at levels up to 18% in the diets of laying ducks without affecting laying performance, egg quality, and antioxidant status. Increasing amounts of corn DDGS linearly increased egg yolk concentrations of key fatty acids like like C18:2n-6 and C18:3n-3 and the antioxidant enzyme activity of GSH-Px through the Nrf2 pathway to avoid oxidative stress.

Estimation of L-threonine requirements for Longyan laying ducks

Objective

A study was conducted to test six threonine (Thr) levels (0.39%, 0.44%, 0.49%, 0.54%, 0.59%, and 0.64%) to estimate the optimal dietary Thr requirements for Longyan laying ducks from 17 to 45 wk of age.

Methods

Nine hundred Longyan ducks aged 17 wk were assigned randomly to the six dietary treatments, where each treatment comprised six replicate pens with 25 ducks per pen.

Results

Increasing the Thr level enhanced egg production, egg weight, egg mass, and the feed conversion ratio (FCR) (linearly or quadratically; p<0.05). The Haugh unit score, yolk color, albumen height, and the weight, percentage, thickness, and breaking strength of the eggshell did not response to increases in the Thr levels, but the albumen weight and its proportion increased significantly (p<0.05), whereas the yolk weight and its proportion decreased significantly as the Thr levels increased.

Conclusion

According to a regression model, the optimal Thr requirement for egg production, egg mass, and FCR in Longyan ducks is 0.57%, while 0.58% is the optimal level for egg weight from 17 to 45 wk of age.

Nutritional factors affecting abdominal fat deposition in poultry: a review

The major goals of the poultry industry are to increase the carcass yield and to reduce carcass fatness, mainly the abdominal fat pad. The increase in poultry meat consumption has guided the selection process toward fast-growing broilers with a reduced feed conversion ratio. Intensive selection has led to great improvements in economic traits such as body weight gain, feed efficiency, and breast yield to meet the demands of consumers, but modern commercial chickens exhibit excessive fat accumulation in the abdomen area. However, dietary composition and feeding strategies may offer practical and efficient solutions for reducing body fat deposition in modern poultry strains. Thus, the regulation of lipid metabolism to reduce the abdominal fat content based on dietary composition and feeding strategy, as well as elucidating their effects on the key enzymes associated with lipid metabolism, could facilitate the production of lean meat and help to understand the fat-lowering effects of diet and different feeding strategies.

Dietary alpha lipoic Acid improves body composition, meat quality and decreases collagen content in muscle of broiler chickens

A total of 192 broiler chicks were used to evaluate the influence of dietary α-lipoic acid (ALA) on growth performance, carcass characteristics and meat quality of broiler chickens with the purpose of developing a strategy to prevent the occurrence of pale, soft, and exudative (PSE) meat and to improve the meat quality of broilers. At 22 d of age, birds were allocated to 4 ALA treatments (0, 400, 800, and 1200 ppm). The results showed that dietary ALA significantly decreased average feed intake (AFI), average daily gain (ADG), final live body weight (BW) and carcass weight (p<0.05), while no difference in feed conversion ratio (FCR) was detected among chickens fed with and without ALA. Abdominal fat weight significantly decreased (p<0.05) for broilers fed 800 and 1200 ppm ALA. However when calculated as the percentage of carcass weight there was no significant difference between control and ALA treatments. Meat quality measurements showed that dietary ALA regulated postmortem glycolysis and improved meat quality as evidenced by increased muscle pH and decreased drip loss of meat (p<0.05). Although ALA did not change the tenderness of meat as indicated by meat shear force, dietary ALA decreased collagen content and mRNA expression of COL3A1 gene (p<0.05). In conclusion, the results indicate that dietary ALA may contribute to the improvement of meat quality in broilers.