Effects of Spirulina algae as a feed supplement on nutritional value and flavour components of silkie hens eggs

Transcriptome and proteome revealed the differences in 3 colors of earlobe in Jiangshan Black-bone chicken

The earlobe is a featherless, exposed thickening located beneath the ear canal of chickens, which plays a visual signaling role in age, performance, mental vitality, reproduction, and other aspects. However, despite its importance, there have been few studies on the color differences and formation mechanisms of chicken earlobes, particularly the structurally blue earlobes characteristic of the Jiangshan black-bone chicken. In this study, we explored the physiological mechanisms that may influence the formation of differently colored earlobes using 3 types of earlobes from Jiangshan black-bone chickens: light peacock green (Green group), dark peacock green (Blue group), and dark reddish purple (Black group). All 3 earlobe colors exhibited positive melanin Masson-Fontana staining, and the thickness of collagen fibers in the dermis decreased in the order of Green, Blue, and Black groups. A total of 1,953 differentially expressed genes (DEGs) were detected in the 3 earlobes through mRNA sequencing, among which the GO term "collagen trimer" was significantly enriched in DEGs between groups. Additionally, 716 differentially expressed proteins (DEPs) were identified in the 3 earlobes using 4D-DIA proteomics, with the term "collagen fibril organization" being significantly enriched in DEPs between the Green and Black groups. Integrated analysis of transcriptome and proteome data revealed that 12 DEGs and DEPs were commonly differentially expressed between the Green and Black groups, including the gene LUM (corneal keratan sulfate proteoglycan), which was significantly enriched in the "collagen fibril organization" GO term. In conclusion, our study suggests that LUM plays a crucial role in the formation of peacock green earlobes in Jiangshan black-bone chickens. The high level of LUM in peacock green (Green and Blue groups) may affect collagen nanostructures, leading to a stronger effect of melanin-supported dermal collagen on the production of non-iridescent structural colors through coherent scattering, resulting in a bright structural blue color in Jiangshan black-bone chickens. In contrast, the low expression of LUM in dark reddish purple (Black group) reduces the reflection of non-iridescent structural colors, making the earlobe color appear almost black, similar to melanin.

Hypocholesterolemic, Antioxidative, and Anti-Inflammatory Effects of Dietary Spirulina platensisis Supplementation on Laying Hens Exposed to Cyclic Heat Stress

This study aimed to investigate the role of dietary Spirulina platensis (SP) supplementation in relieving the negative impacts of heat stress (HS) on the productive performance, cholesterol profile, redox status, and inflammatory cytokines of laying hens. A total of 288, 45-wk-old and 1550.7 ± 2.3 g initial body weight, HY-Line W-36 laying hens were housed in two environmental-controlled compartments. Layers were allotted to eight treatments of a two × four factorial design, with six replicates containing six birds per treatment. The temperature in one of the compartments was kept at a thermoneutral condition (24 °C group), while the temperature in the other compartment was raised to a cyclic heat stress of 35 °C from 9:00 a.m. to 5.00 p.m. (35 °C group). Layers in each compartment were fed on one of four experimental diets, containing 0%, 3%, 6%, or 9% SP (SP groups). The trial continued for five weeks. As a result of this study, exposure of laying hens to cyclic HS resulted in a significant (p < 0.05) increase in the total cholesterol (CH), low-density lipoprotein-CH, liver- and egg yolk-CH, ceruloplasmin, malondialdehyde, interleukins (IL-1β and IL-6), and tumor necrosis factor-α, and a significant (p < 0.05) decrease in the high-density lipoprotein-CH, total antioxidant capacity, and reduced glutathione levels. HS negatively (p < 0.05) affected the hen−day egg production (EP, 90.5% vs. 77.0%), egg weight (EW, 61.8 g vs. 56.8 g), feed intake (FI, 111.6 g vs. 101.5 g) and feed conversion ratio (FCR, 2.00 vs. 2.37). As SP levels increased in layer diets, a linear (p < 0.05) improvement response in most of the parameters was obtained in both HS and non-HS layers, recording the best results with 9% SP (e.g., 78.8% vs. 87.6% EP, 56.7 g vs. 61.9 g EW, 103.3 g vs. 110.2 g FI, and 2.38 vs. 2.04 FCR, in 0% vs. 9% SP, respectively). When incorporating SP into the diets of HS-layers, the negative impacts of HS were remarkably relieved (p < 0.05). Therefore, diets containing 9% SP could be used as a promising approach to improve the productive and physiological performance of laying hens, particularly under heat stress conditions.

Short-Term Spirulina (Spirulina platensis) Supplementation and Laying Hen Strain Effects on Eggs' Lipid Profile and Stability

Simple Summary

Spirulina is an alga rich in micronutrients of interest for improving the nutritional value and quality of the products. This study evaluates the transfer of some of these micronutrients (vitamins and fatty acids) in egg yolk when short periods of supplementation are used in hens of two different strains, and its consequent effects on some quality parameters. Short-term spirulina supplementation markedly modified vitamin content and color in yolk. Hen strain mainly affected the fatty acid profile, and a different response to retinol content and fatty acid proportions (mainly monounsaturated and desaturase activity) according to spirulina supplementation and breed of hens was observed.

Abstract

The aim of the study was to investigate the effect of short-term dietary spirulina supplementation (1% and 3%) and the strain of laying hens (White Leghorn: WL and Rhode Island Red: RIR) on color, nutritional value, and stability of yolk. Egg weight was not affected by any of the studied effects. Yolks from 3%-spirulina supplemented hens had higher retinol and lower α-tocopherol content (p = 0.0001) when compared to control. The supplementation with 1%-spirulina markedly decreased luminosity and increased redness (p = 0.0001) and yellowness (p = 0.0103). Short-term spirulina supplementation slightly modified the fatty acid composition of yolk. The C16-desaturase index increased with the algae, whereas other egg quality indices (hypocholesterolemic, thrombombogenic, n-6/n-3) were not modified. Hen strain mainly affected to the lipid profile. The RIR hens accumulated greater yolk retinol with supplementation doses of 3% (p < 0.05), while the WL hardly suffered changes in the accumulation. Also, yolks from RIR hens had lower C16:0 (p = 0.0001), C18:0 (p = 0.0001), saturated (SAT) (p = 0.0001), and thrombogenic index (p = 0.0001), C20:3n-6 (p = 0.0001), n-6/n-3 ratio (p = 0.003), Δ-6+5-desaturase (p = 0.0005), total elongase indices (p = 0.0001) when compared to WL. Moreover, RIR had higher monounsaturated (MUFA), Δ-9-desaturase and hypocholesterolemic indices (p < 0.05) than WL. A different response to spirulina supplementation was observed for C18:1n-9, MUFA, Δ-9-desaturase and thiesterase indices (p < 0.05) according to hen strain. Yolks from RIR had higher MUFA and Δ-9-desaturase indices than WL at 1%-spirulina supplementation, whereas these parameters were less affected in RIR supplemented with 3%. SAT and Δ-9-desaturase were significantly correlated (r = −0.38 and 0.47, respectively) with retinol content according to a linear adjustment (p < 0.05). Lipid oxidation of yolk was slightly modified by the dietary treatment or hen strain. It was detected a relationship between TBARS and α-tocopherol, C22:5n-3 or C22:6n-3 (p < 0.05). L* and a* were also inversely or positively related with yolk retinol content according to a linear response (p < 0.05). The administration of 1% of spirulina in diets of red hens would be an interesting alternative to get healthier eggs from the nutritional point of view, obtaining an adequate color and without modifications in other yolk quality traits.

Influence of Different Tetracycline Antimicrobial Therapy of Mycoplasma (Mycoplasma synoviae) in Laying Hens Compared to Tea Tree Essential Oil on Table Egg Quality and Antibiotic Residues

The food of animal origin that is the most consumed is the table egg, but laying hens treated with antibiotics can produce eggs contaminated with antibiotic residues. Residues of antibiotics may present a risk for consumer health. Keeping in mind that laying hens almost always suffer from Mycoplasma (Mycoplasma synoviae), for which they are treated with antibiotics, high-quality egg production is even harder. Our research aimed to investigate the influence of three different antibiotics compared to the tea tree (Melaleuca alternifolia) essential oil administered to naturally infected laying hens with M. synoviae, on antibiotic residues in eggs as well as the egg nutritive and sensory qualities. A total of 20,000 laying hens, housed in one facility and divided into four lines each consisting of 5000 hens naturally infected with M. synoviae, was used. For the antimicrobial therapy, tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) were used, respectively. As a control, tea tree essential oil (TT) was used. Based on the gained results all tetracyclines treatment residue values were significantly (p < 0.05) higher compared to the control treatment (TT), but without any significant differences (p > 0.05) between themselves. The results showed no differences in the nutritive and the sensory qualities of eggs between the control and the experimental treatments (p > 0.05). Keeping in mind the obtained results from this study, it can be concluded that tea tree essential oil could be successfully used as a natural antibiotic in the treatment of M. synoviae, without any adverse effects on table egg quality.