Dietary Soybean Oil Supplementation Affects Keel Bone Characters and Daily Feed Intake but Not Egg Production and Quality in Laying Hens Housed in Furnished Cages

Effects of long-term intake of carotenoid-enriched eggs on healthy people: a randomized controlled study

Red palm oil, a natural repository abundant in tocotrienols, tocopherols and carotenoids, is frequently employed as a pigment and nutritional enhancer in food products. The principal aim of this study is to explore the disparities in vitamin A levels, fatty acid profiles and gut microbiota among healthy adults who consume carotenoid-enriched eggs compared to those who consume normal eggs. A total of 200 hens were randomly assigned to either the red palm oil group or the soybean oil group, with the objective of producing carotenoid-enriched eggs and normal eggs. Throughout a six-month, double-blinded, randomized controlled trial, participants were instructed to consume one carotenoid-enriched or normal egg daily at a fixed time. Fecal and blood samples were collected from the participants at the start and conclusion of the six-month intervention period for further analysis. Our findings indicated that there was no significant change in the vitamin A level for daily supplementation with one carotenoid-enriched egg, but there were significant changes in some indicators of fatty acid profiles and gut microbiota compared to the control group of the population. Nonetheless, the consumption of eggs, regardless of carotenoid-enriched eggs or normal eggs, positively influenced dietary habits by reducing the intake of saturated fatty acids and enhancing the intake of monounsaturated and polyunsaturated fatty acids of the population.

Fermented calcium butyrate supplementation in post-peak laying hens improved ovarian function and tibia quality through the "gut-bone" axis

The compromised egg quality and leg abnormality during the end of the laying cycle (after 40 weeks) have been leading to poor animal welfare and substantial economic losses. Therefore, the effects of fermented calcium (Ca) butyrate, produced by fermentation by Clostridium butyricum, on production, eggshell quality, and tibial property of hens were explored. A total of 192 Hy-line brown laying hens at 50-week-old were assigned to a basal diet or the basal diet with 300 mg/kg of the fermented Ca butyrate from 50 to 58 weeks of age. Each treatment had 6 replicates with 16 hens each. The diet supplemented with 300 mg/kg fermented Ca butyrate notably increased egg weight, ovarian follicle number, and eggshell strength (P = 0.072) as compared to the basal diet, which were associated with cytokine secretion, toll-like receptor signaling pathways, and intestinal immunity based on the RNA-seq data from the granulosa. Dietary Ca butyrate inclusion decreased the expression of ileal tumor necrosis factor-alpha and serum pro-inflammatory cytokine concentration, as well as increased the content of serum immunoglobulin A when compared to the basal diet (both P < 0.05). The birds that received fermented Ca butyrate diets exhibited higher villus height (P < 0.05) and upregulated expression of tight junction proteins, whereas it did not alter the composition of cecal microbiota (P > 0.05). In addition, the diet with fermented Ca butyrate reduced the number of osteoclasts in the proximal tibia and the level of C-terminal cross-linked telopeptide of type I collagen, a bone resorption marker (P < 0.05), whereas it tended to increase the concentration of the procollagen type I N-terminal propeptide that reflects bone formation marker in serum. Moreover, the layers fed fermented Ca butyrate diets possessed higher (P < 0.05) bone area and trabecular number of the proximal tibia, yield load, and ultimate load than those that consumed basal diets. Collectively, dietary fermented Ca butyrate supplementation in post-peak layer diets improved the ovarian function and tibia quality, which might be related to enhancing intestinal integrity and consequently decreasing inflammation mediated bone resorption.

Serum bone remodeling parameters and transcriptome profiling reveal abnormal bone metabolism associated with keel bone fractures in laying hens

Keel bone fractures affect welfare, health, and production performance in laying hens. A total of one hundred and twenty 35-wk-old Hy-line Brown laying hens with normal keel (NK) bone were housed in furnished cages and studied for ten weeks to investigate the underlying mechanism of keel bone fractures. At 45 wk of age, the keel bone state of birds was assessed by palpation and X-ray, and laying hens were recognized as NK and fractured keel (FK) birds according to the presence or absence of fractures in keel bone. The serum samples of 10 NK and 10 FK birds were collected to determine bone metabolism-related indexes and slaughtered to collect keel bones for RNA-sequencing (RNA-seq), Micro-CT, and histopathological staining analyses. The results showed that the concentrations of Ca, phosphorus, calcitonin, 25-hydroxyvitamin D₃, and osteocalcin and activities of alkaline phosphatase and tartrate-resistant acid phosphatase (TRAP) in serum samples of FK birds were lower than those of NK birds (P < 0.05), but the concentrations of parathyroid hormone, osteoprotegerin, and corticosterone in serum samples of FK birds were higher than those of NK birds (P < 0.05). TRAP staining displayed that FK bone increased the number of osteoclasts (P < 0.05). Micro-CT analysis indicated that FK bone decreased bone mineral density (P < 0.05). Transcriptome sequencing analysis of NK and FK bones identified 214 differentially expressed genes (DEGs) (|log2FoldChange| > 1, P < 0.05), among which 88 were upregulated and 126 downregulated. Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) analysis indicated that 14 DEGs related to skeletal muscle movement and bone Ca transport (COL6A1, COL6A2, COL6A3, PDGFA, MYLK2, EGF, CAV3, ADRA1D, BDKRB1, CACNA1S, TNN, TNNC1, TNNC2, and RYR3) were enriched in focal adhesion and Ca signaling pathway, regulating bone quality. This study suggests that abnormal bone metabolism related to keel bone fractures is possibly responded to fracture healing in laying hens.

Combination of Cinnamaldehyde with Carvacrol or Thymol Improves the Mechanical Properties of Tibia in Post-Peak Laying Hens

Roles of plant-derived cinnamaldehyde, carvacrol, and thymol in the gut and bone health of laying hens was evaluated in the present study. After acclimation for 2 weeks, a total 384 of 52-week-old laying hens were allocated into three groups for 6 weeks: (1) basal diet group (Ctrl), (2) combination of cinnamaldehyde with carvacrol group (CAR+CIN), and (3) blend of cinnamaldehyde with thymol (THY+CIN). The dietary essential oil level was 100 mg/kg. Each treatment group had eight replicate pens (16 birds/pen). The stiffness and ultimate load of the tibiae from both the CAR+CIN and THY+CIN groups were higher than that of the Ctrl group (p < 0.05), along with comparable tibia ash, calcium, and phosphorus content among groups. At the same time, the manipulation of essential oils upregulated the transcription abundances of intestinal barrier proteins to varying degrees, whereas the experimental treatment failed to affect the composition in phyla of cecal microbiota. When compared to the Ctrl group, birds fed the CAR+CIN and THY+CIN diet displayed decreased bone resorption markers, reduced interleukin-1 concentrations, and increased transforming growth factor beta levels in serum. These findings suggest that cinnamaldehyde with carvacrol or thymol in feed of hens could enhance intestinal barrier and improve the mechanical properties of tibiae through structural modelling but not increase the mineral density, which might be involved in suppressing inflammation-mediated bone resorption.

Keel bone damage affects behavioral and physiological responses related to stress and fear in two strains of laying hens

Keel bone damage (KBD) is more prevalent in alternative laying hen housing systems than in conventional cages, and its incidence differs from strain to strain. However, the information of KBD in Lindian chickens, a native Chinese strain, is limited. To investigate the effect of KBD on fearfulness and physiological indicators of stress in Lindian chickens and commercial laying hens, a total of two hundred 25-wk-old chickens (100 Hy-line Brown and 100 Lindian chickens) were studied for 7 wk. The birds were housed in furnished cages with 10 birds per cage for each strain. At 32-wk of age, the birds in each strain were divided into normal (NK), deviated (DK), and fractured (FK) hens according to the keel bone status. Ten birds in each keel bone status per strain were subsequently selected to collect blood for the determination of stress and fear-related indicators, including corticosterone, serotonin, interleukin-1β, and interleukin-6, and measure fear responses, including novel object test (NOT), human approach test (HAT), and tonic immobility (TI) test. The results showed that egg production was lower and the incidence of keel bone fractures was higher in Lindian chickens than in Hy-line Brown hens (P < 0.05). Lindian chickens showed a significantly increased whole blood serotonin content, NOT-latency, HAT-score, and TI induction times (P < 0.05) and decreased serum interleukin-6 content and TI-duration (P < 0.05) compared with Hy-line Brown hens. Additionally, FK hens had significantly elevated whole blood corticosterone, serum interleukin-1β and interleukin-6 levels, TI-duration, and NOT-latency (P < 0.05), and a reduced whole blood serotonin content (P < 0.05) compared with NK and DK hens. Our results indicated that KBD affected stress and fear responses, and this impact was mainly reflected by FK hens compared with NK and DK hens. We suggest that keel bone fractures are the main factor impairing hen welfare. Besides, the incidence of keel bone fractures and stress and fear responses of Lindian chickens are more severe than Hy-line Brown laying hens, indicating that the strain type can affect the health and welfare of laying hens.

Effects of Oil Types and Fat Concentrations on Production Performance, Egg Quality, and Antioxidant Capacity of Laying Hens

In this study, soybean oil, lard and mixed oils were added to the feed in two concentrations (1.5% and 3% of each), resulting in six experimental groups. The control group was fed with a base diet without additions, and used to compare the effects of feeding on production performance and egg quality of laying hens. The results demonstrated that: (1) the 3% supplemented-oils or lard group showed a decrease in laying rate; (2) 1.5% and 3% added-lard significantly increased the total amount of unsaturated fatty acids in eggs, compared to the control group; (3) 1.5% and 3% soybean oil increased the content of mono/polyunsaturated fatty acids, cholesterol, phospholipids and choline in eggs; (4) glutathione peroxidase (GPx) and superoxide dismutase (SOD) contents were increased in all groups, being the most evident in the lard-treated group; (5) all experimental groups showed an increase in the content of essential and non-essential amino acids in albumen; (6) 3% oils, especially the mixed oils, damaged the structure of globules of cooked egg yolks. Therefore, the use of 1.5% soybean oil in the feed diet of Hyline brown hens resulted in the most adequate oil to ensure animal health and economic significant improvements in this experiment.