Restricted feeding could enhance feed conversion ratio and egg quality of laying Japanese quail kept under different stocking densities

Sex-specific effects of dietary restriction on physiological variables in Japanese quails

Nutritional limitation is a common phenomenon in nature that leads to trade-offs among processes competing for limited resources. These trade-offs are mediated by changes in physiological traits such as growth factors and circulating lipids. However, studies addressing the sex-specific effect of nutritional deficiency on these physiological variables are limited in birds. We used dietary restriction to mimic the depletion of resources to various degrees and investigated sex-specific effects on circulating levels of insulin-like growth factor 1 (IGF-1) and triglycerides in Japanese quails (Coturnix japonica) subjected to ad libitum, 20%, 30% or 40% restriction of their daily requirement, for 2 weeks. We also explored the association of both physiological variables with body mass and egg production. While dietary restriction showed no effects on circulating IGF-1, this hormone exhibited a marked sexual difference, with females having 64.7% higher IGF-1 levels than males. Dietary restriction significantly reduced plasma triglyceride levels in both sexes. Females showed more than six-fold higher triglyceride levels than males. Triglyceride levels were positively associated with body mass in females while showed not association in males. Overall, our findings revealed sex-specific expression of physiological variables under dietary restriction conditions, which coincide with body size.

Dietary restriction and life-history trade-offs: insights into mTOR pathway regulation and reproductive investment in Japanese quail

Resources are needed for growth, reproduction and survival, and organisms must trade off limited resources among competing processes. Nutritional availability in organisms is sensed and monitored by nutrient-sensing pathways that can trigger physiological changes or alter gene expression. Previous studies have proposed that one such signalling pathway, the mechanistic target of rapamycin (mTOR), underpins a form of adaptive plasticity when individuals encounter constraints in their energy budget. Despite the fundamental importance of this process in evolutionary biology, how nutritional limitation is regulated through the expression of genes governing this pathway and its consequential effects on fitness remain understudied, particularly in birds. We used dietary restriction to simulate resource depletion and examined its effects on body mass, reproduction and gene expression in Japanese quails (Coturnix japonica). Quails were subjected to feeding at 20%, 30% and 40% restriction levels or ad libitum for 2 weeks. All restricted groups exhibited reduced body mass, whereas reductions in the number and mass of eggs were observed only under more severe restrictions. Additionally, dietary restriction led to decreased expression of mTOR and insulin-like growth factor 1 (IGF1), whereas the ribosomal protein S6 kinase 1 (RPS6K1) and autophagy-related genes (ATG9A and ATG5) were upregulated. The pattern in which mTOR responded to restriction was similar to that for body mass. Regardless of the treatment, proportionally higher reproductive investment was associated with individual variation in mTOR expression. These findings reveal the connection between dietary intake and the expression of mTOR and related genes in this pathway.

Effect of feed restriction on growth performance, carcass traits, and some hematological and blood biochemical parameters in growing rabbits

Sixty-four male New Zealand White rabbits, 4 weeks old, were used to study the effects of feed restriction (FR) on growth performance, carcass traits, and some blood parameters. Rabbits were randomly allotted to 4 equal groups. The first group was fed ad libitum (control group). The second, third, and fourth groups were restricted from 4 to 8 (R4-8), 8 to 12 (R8-12), and 4 to 12 (R4-12) weeks of age, respectively. Restricted groups were fed 85% of the control. Means of live body weights (LBW), average daily gain weights (ADGW), relative growth rate (RGR) were calculated. Carcass traits and blood parameters were measured. Results showed that, FR reduced LBW, ADGW and RGR in R4-8 and R4-12 groups. However, FR did not impair the previous traits in R8-12 group. Carcass weight was not impaired in R8-12 group. However, FR reduced kidney fat in all restricted groups. Feed restriction reduced hemoglobin, red blood cell (RBC) and platelet levels in R4-8 and/or R4-12 groups. However, RBC and platelet levels were not altered in R8-12 group. Conclusively, FR impaired growth performance, carcass weight and blood parameters in R4-8 and R4-12 groups, however, the previous traits were not impaired in R8-12 group.

Performance, blood biochemistry, carcass fatty acids, antioxidant status, and HSP70 gene expressions in Japanese quails reared under high stocking density: the effects of grape seed powder and meal

Japanese quails reared under high stocking density (SD) were evaluated for the effects of grape seed powder (GSP) and meal (GSM) supplementation on performance, blood biochemistry, thigh and breast muscle fatty acids, antioxidant status, and HSP70 gene expression. We randomly assigned 288 (15-day-old) quail chicks to six treatment groups in a factorial design (2 × 3) with four replicates, involving two density levels [160 cm²/bird (LD) and 80 cm²/bird (HD)] and three feed forms (FFs) [no supplementation, grape seed powder (3% GSP), grape seed meal (3% GSM)]. SD had a significant effect on live weight, but not on weekly feed intake, daily weight gain, and feed conversion ratio. Serum creatinine and aspartate aminotransferase levels were significantly affected by FF and SD × FF (p < 0.05). A high SD reduced the n-3/n-6 ratio of breast muscle and a significant interaction was found between FF (p < 0.001). The SD × FF interaction reduced the Σn-6 ratio in HDM's thigh muscle, whereas in LDM, the ratio increased (p < 0.01). At high SD, neither GSP nor GSM reduced biological markers of oxidative stress (p > 0.05). Compared to GSP, GSM had higher efficacy at reducing HSP70 levels related to high SD levels. Despite this, at high SD, a diet containing 3% of GSP and GSM was not effective in overcoming oxidative stress. Therefore, more studies using different doses of GSM and GSP in quail diets would be beneficial.

Effects of non-fasting molting on performance, oxidative stress, intestinal morphology, and liver health of laying hens

Animal welfare concerns in laying-hen production facilities have necessitated research on alternative strategies for improving egg production and hen health. At present, most laying-hen facilities in China use the fasting method, but with international emphasis on animal welfare, scholars have begun to find ways to improve production efficiency while ensuring animal welfare standards are adhered to. Therefore, this study investigated the effects of non-fasting molting on production performance, oxidative stress, intestinal morphology, and liver health of laying hens. A total of 180 healthy 90-week-old Dawu Jinfeng laying hens with similar body weights and laying rates (76 ± 2%) were randomly divided into three groups, with five replicates per group and 12 hens per replicate. The hens in the experimental group (NF) were molted using the non-fasting method, the negative control group (C) was not treated with centralized molting, and the positive control group (F) was molted using the fasting method. The results showed that: (1) During the molting period, the laying rate in the NF group (10.58%) decreased and was significantly lower than that in the other two groups (P < 0.05). During the secondary laying peak period, the laying rate in the NF group was highest (89.71%); significantly higher than that in the C group (P < 0.05). (2) During the molting period, compared to the C group, the NF group showed a significant decrease and increase in the total antioxidant capacity (T-AOC) and superoxide dismutase (T-SOD) activity, respectively (P < 0.05). During the secondary laying peak period, the T-SOD activity of the NF group was significantly lower than that of the C group (P < 0.05). (3) During the molting period, the villus height (VH) and the ratios of VH to crypt depth (V/C) of the duodenum, jejunum, and ileum in the NF group were significantly lower than those in the C group (P < 0.05). At the secondary laying peak period, the jejunum V/C was significantly higher than that in the C group (P < 0.05), whereas in the duodenum and ileum it increased but not significantly (P > 0.05). (4) During the molting period, serum glutathione transaminase (AST) and glutathione alanine transaminase (ALT) activities were significantly higher (P < 0.05), and very low-density lipoprotein (VLDL) content and liver weight were significantly lower (P < 0.05) in the non-fasted and fasted groups. However, there was a low degree of liver injury (cell boundary still visible) in the NF group. At the secondary laying peak period, there was no significant difference (P > 0.05) in the indices among the three groups and the liver returned to normal. In summary, non-fasting molting can improve the production performance of laying hens in the later stages, ensure the welfare and health of animals, and provide a theoretical basis for the efficient production of laying hens.

Efficacy of dietary inclusion of biologically treated pruning peach trees by-products on growth performance, blood biochemicals and economic efficiency of New Zealand White rabbits

This work examined the influences of partial replacement of clover hay with 15 or 30% of untreated pruning peach trees by-products (UPPT) or those biologically treated (BTPPT) with effective microorganisms (EM1) on growing rabbit performance. Seventy-five NZW weaned rabbits (6-weeks-old; average body weight 657 g) were assigned randomly into five groups. Five pelleted diets were used, control and other four diets (15 or 30% UPPT or BTPPT were replaced of clover hay). The biological treatments improved the chemical composition of pruning peach trees by-product, in terms of increasing crude protein and decreasing crude fiber as compared to UPPT. Final body weight, body weight gain, feed conversion ratio and performance index values were enhanced when rabbits fed either 15 or 30% BTPPT. Digestibilities of crude protein, crude fiber, nitrogen free extract, total digestible nutrients and digestible energy were increased with rabbits fed diets containing BTPPT. Carcass traits studied, moisture, crude protein (CP), ash, ether extract (EE) of rabbits meat, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities, total cholesterol, creatinine and urea were not different between the applied treatments. Net revenue and economic efficiency were increased with the biological treatment. Conclusively, BTPPT could be used up to 30% with positive effects on growth performance, physiological functions and economic efficiency in NZW growing rabbits.

Role of clay in detoxification of aflatoxin B1 in growing Japanese quail with reference to gender

The present study investigated the influence of the quail diet polluted with aflatoxin B₁ (AFB₁) and its detoxification by using clay as a feed additive on the growth performance and some blood biochemical components of growing Japanese quail with reference to sex. A total number of 120 Japanese quail chicks (1 week old), was randomly divided into 10 groups (24 chicks/ group). A 5 × 2 factorial arrangement experiment was performed and included five levels of AFB₁ (0 ppm, 1 mg/kg AFB₁, 1 mg/kg AFB₁ + 1% clay, 2 mg/kg AFB₁ and 2 mg/kg AFB₁ + 1% clay) and two sexes. Birds fed with aflatoxin free diet had significantly (P ≤ 0.05 and 0.01) higher final live body weight, weight gain and lower mortality rate than the other groups. Addition of 1% clay significantly (P ≤ 0.05 and 0.01) improved the growth performance traits and diminished aflatoxin effect when compared to groups without the addition of clay. Obtained results indicated significant (P ≤ 0.05) differences between the two sexes in their response to aflatoxicosis in the final live body weight and weight gain. Our results showed significant (P ≤ 0.01) changes in all blood biochemicals (total protein, albumin, globulin, total cholesterol, creatinine, uric acid) and activities of serum enzymes studied due to the toxicity of AFB₁. Conclusively, the consumption of polluted diets with AFB₁ caused deleterious effects on the growth performance and blood biochemicals components of Japanese quail, while dietary addition of natural clay to the diet of growing Japanese quail caused beneficial effects.

Effects of ecofriendly synthesized calcium nanoparticles with biocompatible Sargassum latifolium algae extract supplementation on egg quality and scanning electron microscopy images of the eggshell of aged laying hens

In the present study, 200 Brown commercial egg-type layers (60 wk old) were used to study the effects of different levels of ecofriendly synthesis of calcium (Ca) nanoparticles (0.0, 0.50, 1.0, and 1.5 g/kg diet) with biocompatible Sargassum latifolium algae extract (SL-CaNps) on exterior egg quality traits, electronic microscopic view of eggshells, Ca and phosphorus (P) retention, serum Ca and P concentrations, and the histology of the uterus. Hens fed with dietary SL-CaNps powder had higher egg weight and shell weight % values than those of the control group. All SL-CaNps treatment groups had the greatest values of shell weight per unit surface area and shell thickness. Dietary supplementation of SL-CaNps at graded levels up to 1.5 g/kg diet had higher serum Ca and inorganic P levels than that of the control. Laying hens fed with SL-CaNps-added diets had beneficial effects on shell ultrastructure in terms of well-developed palisade and mammillary layers. The numbers of apical cells along the branched tubular gland were greater in SL-CaNps-treated groups than those of control. Conclusively, supplementing SL-CaNps powder up to 1.5 g/kg to the diet of laying hens improved eggshell thickness, shell weight% and shell weight per unit surface and has no adverse effect on their eggshell quality or electronic microscopic view of their eggshell.