Effect of Lighting Methods on the Production, Behavior and Meat Quality Parameters of Broiler Chickens

Many farms have been replacing traditional lighting sources with light-emitting diode (LED) bulbs because of technological modernization. We aimed to investigate the effects of incandescent lighting (IL) and LED lighting on Cobb 500 broiler chickens for six weeks. Production parameters (body weight, feed consumption, feed conversion ratio), calculated slaughter values (yield%, relative breast%, thigh%) and breast meat quality parameters (pH at 45 min and 24 h postmortem, color, drip loss, kitchen equipment losses, shear force, meat composition) were recorded. Non-stop recordings were used to analyze the behavior of the birds during several periods of rearing. The LED group was significantly better in the body weight parameter between week 1 and 5 and the feed conversion ratio between week 2 and 3. The most significant difference in behavior was observed in the middle of the rearing period. The chickens in the LED group spent more time eating, drinking and interacting, and rested less. There was no difference in the meat quality parameters; only shear force was significantly lower in the LED group (1781.9 g/s vs. 2098.8 g/s). According to our results, LED lighting can bring about positive changes in animal production efficiency, behavior and other important characteristics for meat consumers.

Heat shock proteins as a key defense mechanism in poultry production under heat stress conditions

Over the past years, the poultry industry has been assigned to greater production performance but has become highly sensitive to environmental changes. The average world temperature has recently risen and is predicted to continue rising. In open-sided houses, poultry species confront high outside temperatures, which cause heat stress (HS) problems. Cellular responses are vital in poultry, as they may lead to identifying confirmed HS biomarkers. Heat shock proteins (HSP) are highly preserved protein families that play a significant role in cell function and cytoprotection against various stressors, including HS. The optimal response in which the cell survives the HS elevates HSP levels that prevent cellular proteins from damage caused by HS. The HSP have chaperonic action to ensure that stress-denatured proteins are folded, unfolded, and refolded. The HSP70 and HSP90 are the primary HSP in poultry with a defensive function during HS. HSP70 was the optimal biological marker for assessing HS among the HSP studied. The current review attempts to ascertain the value of HSP as a heat stress defense mechanism in poultry.

Intermittent light program impacts on reproductive performance, health and welfare of breeding hens

The lighting regime significantly impacts poultry production, reproductive performance, health and welfare. This study aimed to test the effect of the intermittent light (IL) regime on reproductive organs and hormones, semen quality, and behavioral performance. Thus, 270 Rhode Island Red hens aged 20 weeks were distributed among three groups of six replicates and 15 birds each, housed in floor pens. The first group was used as a control (C) and was exposed to constant light for 16 h d- 1 , while birds in other groups were exposed to IL for 20 min h- 1 (T20) and 40 min h- 1 (T40) during the 16 h light period. The outcomes were that follicle number was higher for T20 compared to T40 but not the controls, while T40 is different from T20 but not the controls. The same is true for testosterone. The sperm concentration is lower for T40 compared to the controls, with no difference between T20 and the controls. Body temperature was not different among groups. Conversely, differences were not noticed for leg alterations; plumage conditions; and relative ovary, oviduct, and/or testes weight and hatchability. Thus, the IL T20 program should be further investigated as a lighting regimen for managing Rhode Island Red laying hens for stimulating follicle number and testosterone without negatively impacting the physiological response and health traits. From a practical point of view, the IL schedule of 20 min h- 1 during 20-36 weeks of age can be economically viable due to saving 66 % of the light cost.

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.

Restricted feeding regimens improve white striping associated muscular defects in broiler chickens

The current study investigated the effects of intermittent feeding (IF) and fasting strategies at different times post-hatch on muscle growth and white striping (WS) breast development. In the first trial, 32 one-day-old Abor Acre broilers were fed ad libitum (AL) for 3 d post-hatch and then randomly allotted into 4 feeding strategies including AL, 1h-IF group (1 h IF, 4 times feeding/d, 1 h each time), 1.5h-IF (1.5 h IF, 4 times feeding/d, 1.5 h each time), and fasting (1d acute fasting, 6 d free access to feed) groups and fed for 7 d. Although angiogenic genes including VEGFA, VEGFR1, and VEGFR2, and myogenic genes including MYOG and MYOD were upregulated (P < 0.05), the breast muscle satellite cell (SC) number and PAX7, MYF5 expression were decreased by the IF strategies (P < 0.05). One-day fasting at 6 d of age also upregulated angiogenic genes and MYOD expression (P < 0.05), downregulated MYF5 expression (P < 0.05), but did not change SC number (P > 0.05). In the second trial, 384 one-day-old birds were fed AL for 1 wk and then randomly allotted to the above 4 feeding strategies starting at 8 d of age until 42 d of age. Similarly, IF and fasting strategies upregulated the expression of angiogenic and myogenic genes (P < 0.05). Both 1h-IF and 1.5h-IF increased breast muscle SC number (P < 0.05). At slaughter, breast muscle fiber diameter of 1.5h-IF was smaller but the SC number was larger than that of the birds fed AL (P < 0.05). The IF and fasting strategies prevented WS development, and reduced breast WS scores and triglyceride content (P < 0.05) without changing the body weight (P > 0.05). Fasting and 1h-IF reduced the expression of adipogenic genes ZNF423 and PDGFRα (P < 0.05). Moreover, IF and fasting strategies reduced fibrosis in breast muscle and reduced skeletal muscle-specific E3 ubiquitin ligases (TRIM63 and MAFBX) (P < 0.05). Fasting significantly reduced CASPASE-3 in breast muscle (P < 0.05). In conclusion, IF starting in the first week decreases SC number. Compared to AL, IF or fasting promotes muscular angiogenesis, increases SC number, prevents muscle degeneration, and prevents the development of WS without impairing the growth performance of broiler chickens.

The effects of intermittent feeding and cold water on welfare status and meat quality in broiler chickens reared under daily heat stress

This study was aimed to determine the effects of feeding type (ad libitum: AF and intermittent: IF) and water temperature (normal: NW and cold: CW) treatments on welfare status and meat quality in fast-growing broiler chickens reared under daily heat stress between 22 and 42 days of age. The chickens' panting rate and rectal temperature were determined at 4, 5, and 6 weeks of age and twice a week in 3 female and 3 male chickens in each pen. Welfare traits such as foot pad dermatitis (FPD), hock burn (HB), breast burn (BB), and leg problems (LP) were examined individually at 42 days of age. At day 43, 3 male and 3 female chickens per pen were randomly selected and slaughtered after an 8-h fasting period; pH and color (lightness (L*), redness (a*), and yellowness (b*)) of breast and thigh meat were determined. AF × C W chickens had significantly higher panting rates at all ages than the other groups (P < 0.05). While FPD and LP were not affected by feeding type and water temperature treatments, interaction effects on HB and BB were found significant (P < 0.05). The HB and BB levels were the lowest in AF × NW chickens (P < 0.05). While treatments did not change to any color traits in breast meat (P > 0.05), interactions significantly affected the yellowness (b*) value in the thigh (P < 0.05). In conclusion, management practices such as IF and CW in fast-growing broilers could not completely reduce the undesirable effects of heat stress on some welfare and meat quality traits, and in some cases, even caused more negativity.

Influences of vitamin A, L-carnitine, and folic acid in ovo feeding on embryo and hatchling characteristics and general health status in ducks

The current investigation was conducted to test the potential effects of in ovo feeding of vitamin A, L-carnitine, and folic acid on embryonic growth and post-hatch performance. A total of 450 fertile duck eggs were randomly distributed into two experiments of five groups/experiment (255 eggs/experiment and 45 egg/group). The experimental groups were: negative control (non-injected eggs), positive control (eggs were injected with 0.1 ml sterile deionized; DI water/egg), and three other treatments in which vitamin A, L-carnitine, and folic acid were injected (1 mg of each nutrient dissolved in 0.1 ml sterile DI water/egg). All-in ovo injected groups with vitamin A, L-carnitine, and folic acid increased the embryo weight, residual yolk weight, heart weight, hatchability percentage, and embryo length at the 25th day of incubation. At hatching, all micronutrients-in ovo injected treatments increased the duckling's weight, levels of blood hemoglobulin, plasma triiodothyronine, and thyroxin, insulin-like growth factor1, total protein, albumin, and globulin, compared with the controls in both experiments. Conclusively, the in ovo feeding of the present micronutrients showed positive impacts on embryonic development, hatchling health status of ducklings.

Effect of feeding frequency on the growth performance, carcass traits, and apparent nutrient digestibility in geese

This study was conducted to determine the effect of feeding frequency on growth performance, carcass traits, and apparent nutrient digestibility in geese from 28 to 70 D of age. In experiment 1, a total of 240 geese were distributed in a completely randomized design into 4 treatments and 6 replicates of 10 birds each. The treatments were free access to the feeder (ad libitum) and access to the feeder 3, 4, and 5 times daily. Geese fed 3 times daily had a lower (P < 0.05) BW, ADG, and ADFI and a higher (P = 0.064) feed conversion ratio (FCR) from 28 to 41 D of age compared with the other groups. Geese fed 4 times daily had a higher (P < 0.05) ADG and ADFI and a lower (P < 0.05) FCR from 42 to 55 D of age compared with ad libitum fed geese. Geese fed 3 times daily had a higher (P < 0.05) ADG from 56 to 69 D of age than geese fed ad libitum and 4 times daily. No differences (P > 0.05) in BW, ADFI, ADG, and FCR were observed between ad libitum and feeding frequency groups from 28 to 69 D of age. Carcass traits and gastrointestinal development were not affected (P > 0.05) by feeding frequency. In experiment 2, the apparent nutrient digestibility in geese from 71 to 77 D of age fed using different feeding frequencies was determined using the total fecal collection method. Feeding frequency did not affect (P > 0.05) the apparent digestibility of DM, CP, crude ash, calcium, phosphorous, or ether extract in geese. Our study demonstrates for the first time that compensatory growth can be gained by enhancing feed intake when a lower feeding frequency is imposed on geese. Both ad libitum feeding and fixed feeding frequency for 3 to 5 times daily are suitable for geese from 28 to 70 D of age to achieve optimum production.

The length of the feed restriction period affects eating behavior, growth performance, and the development of the proximal part of the gastrointestinal tract of young broilers

We studied the effects of restricting the access to feed on the anticipatory eating behavior, growth performance, and the development of the proximal part of the gastrointestinal tract (GIT) in broilers. The experiment consisted in physical restriction of the access of broilers to feed for 0, 4, 6, or 8 h per day from 7 to 19 D of age. At 10, 13, 16, and 19 D of age, immediately before the start of the feed restriction (FR) period, 2 birds per cage were euthanized to evaluate crop and gizzard development. The experimental design was completely randomized, and the linear (L) and quadratic (Q) effects of fasting length on growth performance and GIT traits were determined. In addition, the effect of broiler age on GIT development was studied. From 7 to 19 D of age, ADFI (L, Q; P ≤ 0.05) and BW gain (L; P ≤ 0.01) decreased as the length of the FR period increased, with most of the differences observed with 6 or more hours of fasting. However, feed conversion ratio was not affected by FR length. The relative weight of the crop (% BW) and its fresh content increased (L; P ≤ 0.001) and the moisture of the digesta (%) decreased (L; P ≤ 0.001) as the FR period increased. The DM content (g) of the crop increased with FR, with most of the differences observed with 6 or more hours of fasting (L, Q; P ≤ 0.001). At 19 D of age, the Lactobacillus spp. count in the crop increased (L; P ≤ 0.05) with increase in the FR period. Fasting did not affect any gizzard trait at any age. In summary, physical restriction of the access to feed for 6 h or more reduced BW gain but did not affect feed conversion ratio in broilers from 7 to 19 D of age. Feed restriction for 4 to 8 h stimulated the anticipatory feeding behavior and crop development in broilers.

Low-density lipoprotein receptor-related protein 1 regulates muscle fiber development in cooperation with related genes to affect meat quality

Low-density lipoprotein receptor-related protein 1 (LRP1) is an important signal protein that is widely involved in physiological processes, such as lipid metabolism, cell movement, and disease processes. However, the relationship between LRP1 and meat quality remains unknown in chickens. The present study aimed to investigate the correlation between LRP1 and meat quality that builds on our preliminary research, as well as to reveal the underlying molecular mechanism of LRP1 on meat-quality traits. The results showed that LRP1 was significantly correlated with shear force (P < 0.05). Several key genes involved in muscle growth and development, including IGF-1, IGFBP-5, IGF-1R, IGF-2, and MyoD, were down-regulated significantly (P < 0.05 or P < 0.01), and MSTN was up-regulated significantly (P < 0.01) in the presence of LRP1 interference. Cell proliferation- or apoptosis-related genes, including PMP22, CDKN2C, and p53, increased significantly (P < 0.05 or P < 0.01), whereas Bcl-x decreased significantly (P < 0.05) in the RNAi group. We conclude that LRP1 regulates muscle fiber development in cooperation with related genes that affect myoblast proliferation and apoptosis, thereby impacting shear force in chickens. This study will provide a valuable resource for biological investigations of muscle growth and meat-quality-related genes in chickens. The results could be useful in identifying candidate genes that could be used for selective breeding to improve meat quality.