This study aimed to evaluate the effects of different probiotic administration methods on productive performance, intestinal health, and visceral organ development in broiler chickens. The study used 400 one-day-old unsexed Lohmann broiler chicks reared for 35 days and randomly allocated into 4 treatments and 5 replicates (20 birds per replicate) using a completely randomized design. The probiotics contained Lactobacillus sp. (2 × 107 CFU/mL), Bacillus sp. (1.6 × 107 CFU/mL), and Streptomyces sp. (7.4 × 109 CFU/mL). The probiotic administration methods included: untreated (control, T1), administered in drinking water (T2), sprayed onto the litter (T3), and administered through drinking water and sprayed onto the litter (T4). Probiotics were supplied at 2 mL/L of drinking water and 80 mL per pen (2 m × 1 m) for the spraying treatment. The results showed that compared to the control, probiotic administration (T2 and T4) improved (p < 0.05) body weight gain, feed intake, and decreased feed conversion ratio (FCR), water intake, mortality, and spleen weight. Intestinal health status improved (p < 0.05), as indicated by increased lactic acid bacteria populations and enhanced villus length, surface area, and crypt depth. Ileum weight (

The study aimed to evaluate the effects of adding Lemuru fish oil and Moringa leaf flour to the diet on the internal organs of broiler chickens. Two hundred broiler chickens were reared from day-old chicks until 35 days old. The treatments applied were T0= diet containing 2% palm oil without Moringa leaf flour; T1= diet containing 2% Lemuru fish oil without Moringa leafflour; T2= diet containing 2% Lemuru fish oil + 1% Moringa leaf flour; T3= diet containing 2% Lemuru fish oil + 2% Moringa leaf flour; and T4= diet containing 2% Lemuru fish oil + 3% Moringa leaf flour. Data were analyzed using one-way analysis of variance (ANOVA), and if significant differences were observed, a further test was conducted using Tukey's test. The results showed that the treatments did not affect (P>0.05) the percentages of internal organ and immune organ weights in broiler. The addition of Lemuru fish oil and Moringa leaf flour to the diet affected the percentages of ileum and cecum weights in broiler. This study concluded that adding Lemuru fish oil and Moringa leaf flour to broiler feed does not negatively affect internal organs and is beneficial for the digestive organs of broiler chickens.

This study aimed to evaluate the effects of diet containing Lemuru fish oil supplemented with iron (Fe), zinc (Zn), and chromium (Cr) on growth performance, blood profile, and internal organ development in Sentul chickens, a native Indonesian breed. There were four experimental diets, each with five replicates, namely T0 (Control), T1 (diet containing 2.5% Lemuru fish oil), T2 (diet containing 2.5% Lemuru fish oil + 20 ppm Fe, 60 ppm Zn, 0.4 ppm Cr), and T3 (diet containing 2.5% Lemuru fish oil + 40 ppm Fe, 120 ppm Zn, 0.8 ppm Cr). Feed and water were provided ad libitum for 84 d. Parameters measured included body weight gain, feed intake, feed conversion ratio, Income Over Feed Cost, relative organ weights, intestinal length and, blood profile. Treatments did not significantly affect growth performance (p>0.05), with body weight at 84 d ranging from 905.70 to 962.93 g/b, feed intake ranging from 2958.15 to 2999.03 g/b and feed conversion ratio between 3.15 and 3.54. Hematological analysis revealed significant effects on erythrocyte and leukocyte counts, as well as lymphocyte percentage, with the highest erythrocyte count in T2 (2.83 × 106/µL) and the highest lymphocyte proportion in T1 (51.76%). Most internal organ weights did not differ significantly, except for the proventriculus. In summary, Lemuru fish oil with Fe, Zn, and Cr supplements did not adversely affect growth performance. When used at moderate dosages, the combination of fish oil and trace minerals improved economic values through IOFC, erythrocyte count, enhanced gut morphology, and immune characteristics, providing information on feeding strategies for native poultry.

The study aimed to evaluate the impact of Zinc oxide nanoparticles (ZnO-NPs) on growth performance, carcass traits, meat color, antioxidant activity, and insuline-like growth factor-1 (IGF-1) gene expression in broiler chickens. This study used 200 Cobb500 broiler chicks aged two days. The observation was conducted for 5 weeks and used a completely randomized design with 4 treatments and 5 replications (10 chicks, each replicates). The treatment were: Control (basal diet); ZnO-NPs 50 (control + 50 mg Zn/kg); ZnO-NPs 75 (control + 75 mg Zn/kg); ZnO-NPs 100 (control + 100 mg Zn/kg). Performance, carcass traits, Zn content and antioxidant activity, meat color, and IGF-1 gene expression were observed. Supplementation of ZnO-NPs (d 1-14) significantly (P < 0.05) increased body weight and improved feed-to-gain ratio, whereas no effects (P > 0.05) were observed on average daily gain, average daily feed intake, or feed-to-gain ratio during days 15-35. Zinc oxide nanoparticles (ZnO-NPs) also significantly (P < 0.05) increased the hue (h*) value while reducing the lightness (L*) and redness (a*) of the breast. Supplementation enhanced Zn deposition and SOD enzyme activity, accompanied by a decrease in MDA concentration in the breast. However, ZnO-NPs did not affect (P > 0.05) carcass traits (percentage of breast, back, thigh, and drumstick meat), nor did the yellowness (b*) and chromaticity (c*) of breast meat and IGF-1 gene expression in the small intestine. Overall, the addition of ZnO-NPs at levels up to 100 mg Zn/kg in broiler chicken feed during the growth phase leads to optimal improvements in performance parameters. Mechanistically, ZnO-NPs function as redox modulators rather than direct antioxidants, eliciting dose-dependent pro-oxidant and antioxidant responses in broiler chickens. This modulatory effect contributes to enhanced antioxidant status, a tendency to support the IGF-1 gene expression profile, and a reduction in oxidative stress. Furthermore, breast meat derived from chickens supplemented with ZnO-NPs demonstrates potential as a functional food with added health benefits.

This study evaluated the effects of Spirulina sp. supplementation combined with vitamin E in laying hen diets on egg physical quality and shell strength during storage under different durations and temperatures. Four dietary treatments were used: T0 (control diet with 100 IU/kg vitamin E), T1 (0.5% Spirulina sp. + 100 IU/kg vitamin E), T2 (1.0% Spirulina sp. + 100 IU/kg vitamin E), and T3 (2.0% Spirulina sp. + 100 IU/kg vitamin E). The experiment employed a completely randomized design with a 4 × 2 × 2 factorial arrangement and five replications. The factors consisted of diet, storage duration (7 and 14 days), and storage temperature (room and refrigerated). Storage duration and temperature significantly (P<0.001) reduced HU, while longer storage significantly decreased yolk and increased albumen percentages (P<0.001). Diet and storage duration significantly (P<0.001) influenced yolk color. Egg weight was not affected by the treatments. In conclusion, dietary treatment significantly affected yolk color and Haugh unit. The 0.5% Spirulina inclusion level resulted in the highest Haugh unit, indicating improved albumen quality, whereas 2.0% Spirulina enhanced yolk pigmentation. Storage temperature influenced internal egg quality, with refrigerated storage better maintaining albumen percentage and Haugh unit compared to room temperature.

The aimed of this study was to evaluate the effects of supplementation of vitamin E and selenium on giblets, malondialdehyde (MDA) in the meat, and carcass quality of broiler chickens. A completely randomized factorial design (CRFD) 2×3 with 3 replications and each used 1 bird, consisting of 2 levels of vitamin E supplementation (0 ppm, 200 ppm) and 3 levels of selenium supplementation (0 ppm, 0.3 ppm, and 0.6 ppm) was used in this experiment. Data were analyzed using analysis of variance (ANOVA). The results showed there was interaction between supplementation of 200 ppm vitamin E and 0.6 ppm selenium in reducing (p<0.05) the weight percentage of kidney and abdominal fat. Supplementation of 200 ppm vitamin E highly significantly reduced (p<0.01) and supplementation of 0.6 ppm selenium significantly reduced (p<0.05) MDA contained in the meat. Supplementation of vitamin E or selenium did not affect the carcass quality. It is concluded that 200 ppm vitamin E or 0.6 ppm selenium supplementation effective as an antioxidant without bothering of carcass production and digestive tract of broiler chickens. Combination of supplementation of 200 ppm vitamin E and 0.6 ppm selenium effective decreased the fat abdominal.

<b>Background and Objective:</b> Fishmeal in Indonesia still mostly comes from abroad, while the available fish waste has not been widely processed as an alternative feed ingredient to replace it. This study aimed to evaluate the effect of feeding fermented fish waste meals in the ration on the physical quality of quail eggs and reproductive organ characteristics. <b>Materials and Methods:</b> One hundred and sixty female quails, 25 weeks old, were reared until 33 weeks. The diet treatments were P0 = Control ration, P1 = Ration containing 2% fermented fish waste meal, P2 = Ration containing 4% fermented fish waste meal and P3 = Ration containing 6% fermented fish waste meal. A completely randomized design (CRD) was used with four treatments and four replications, with ten female quails per replicate. The data were analyzed using ANOVA and if there were significant differences, the data were further analyzed using Duncan's Multiple Range Test. Significance was considered at a probability level of p<0.05. The variables measured were the egg's physical quality and reproductive organs. <b>Results:</b> The treatments did not significantly (p>0.05) affect egg weight, egg shape index, shell thickness, eggshell, albumen, yolk weight percentage, yolk color index, the Haugh unit, the carcass percentage and reproductive tract of quails. However, fermented fish waste meal increased the yolk color index and carcass percentage. <b>Conclusion:</b> Fermented fish waste meal up to 6% had no negative effect on egg quality or reproductive organs of quails. Fermented fish waste meal from pineapple can be considered an alternative feed ingredient, utilizing bromelain enzymes to reduce the use of fish meal.

This study was carried out to evaluate Chitosan Oligoshaccarida (COS) supplementation on TLR4 gene expression, blood profile, and carcass weight in broiler chicken. A total of 100 Lohmann broiler Day Old Chick (DOC) with an initial average body weight of 46 ± 0.7 g were randomly allotted into 2 group treatments with 5 replications (10 unsexed DOC in each pen) for 35 days. Dietary treatments were Basal Diet (BD) without supplement (P0) and BD + COS 100 mg kg-1 (P1). The results showed that treatments with COS 100 mg kg-1 decrease TLR4 mRNA expression level compared to control, but were not differ on blood profile and the ratio between heterophils and lymphocytes which ranged from 0.58-0.87 indicated that chickens experienced moderate to high stress. COS supplementation had the significant differences in carcass weight, where chickens given COS supplementation had a higher carcass weight than the control. In conclusion COS supplementation in broiler feed can significantly increase carcass weight and improve the health status of chickens as seen from blood profile and TLR4 gene expression.

This meta-analysis investigated the impact of protease supplementation on growth performance and gas emissions in broiler diets. A total of 145 individual trials, comprising 852 data points, were included. The results revealed a significant decrease in the feed conversion ratio (FCR), and improvements in body weight gain (BWG) and body weight (BW) due to protease supplementation. The effect sizes were -0.374 (SE=0.029; P<0.001) for FCR, 0.440 (SE=0.031; P<0.001) for BWG, and 0.370 (SE=0.056; P<0.001) for BW. Subgroup analysis revealed greater effectiveness in diets containing up to 21% crude protein and diverse ingredient compositions. However, no significant reduction in ammonia (NH3), hydrogen sulfide (H2S), or methyl mercaptan (CH3SH) emissions was observed. This study revealed that protease supplementation improved broiler growth performance but had a limited impact on gas emissions. Future studies should explore integrating protease supplementation with other synergistic interventions that could have a greater impact on reducing gas emissions.

This study evaluated the effects of cassava (Manihot esculenta Crantz) leaves extract (CLE) in drinking water on the performance and health profile of IPB-D1 chickens. Cassava leaves are known to contain bioactive compounds such as flavonoids, tannins, and saponins which have antioxidant and antibacterial properties. These compounds can provide positive effects such as feed efficiency, improving growth performance and health status of chickens by improving the immune system and reducing oxidative stress. Cassava leaves extract acts as a phytogenic additive that can be given in livestock drinking water. This study used 180 IPB-D1 chickens aged 2–8 weeks were randomly assigned to three treatments: CLE0 (control), CLE1 (17 ml/l CLE), and CLE2 (50 ml/l CLE). Parameters observed included growth performance, organ morphometry, hematological profiles, and ileal histology. Data were analyzed using one-way ANOVA and Tukey’s post hoc test (p<0.05). cassava leaves extract supplementation did not adversely affect growth or feed intake. Final body weight and feed conversion ratio (FCR) were not significantly different among the groups. A reduction in leukocyte counts was observed, particularly in the CLE2 group, with a relative increase in heterophils, though values remained within physiological limits. Histological analysis revealed a significant increase in villus surface area in the CLE2 group, followed by CLE1, compared to the control (CLE0), suggesting enhanced intestinal morphology and nutrient absorption potential. Cassava leaves extract can be given in the drinking water of IPB-D1 chickens without disrupting their performance and health profile. These findings indicate that cassava leaves extract can improve gut structure without compromising performance, supporting its application as a safe and beneficial phytogenic additive in poultry diets.

Pellet quality is a key factor influencing poultry growth performance. The use of carboxymethyl cellulose (CMC) as a pellet binder and protease enzyme supplementation via drinking water may improve nutrient availability and digestive efficiency. This study evaluated the effects of carboxymethyl cellulose (CMC) with varying viscosities and protease enzyme supplementation via drinking water on growth performance in IPB-D1 chicks (n = 250) with five dietary treatments in a Completely Randomized Design (5 replicates of 10 chicks each). Treatment included: a control diet (C0P0), a diet containing 0.5% CMC with a viscosity of 1000–2500 cps (C1P0), the same CMC level and viscosity with 10 mg/L protease enzyme in drinking water (C1P1), a diet containing 0.5% CMC with a viscosity of 2500–4000 cps (C2P0), and the same CMC level and viscosity with 10 mg/L protease enzyme in drinking water (C2P1). Growth performance parameters evaluated included feed intake, water intake, body weight gain, feed conversion ratio (FCR), and mortality. No significant differences (P>0.05) were found across treatments. However, descriptively, the combination of high-viscosity CMC and protease enzyme showed a tendency to improve growth efficiency. This suggests a potential synergistic effect worth further exploration in IPB-D1 chickens.

Poultry nutrition is greatly influenced by genetic composition and developmental stage, with protein intake playing a pivotal role in performance metrics. However, precise feeding guidelines, especially concerning protein levels and the role of bioactive compounds during the starter phase, remain insufficiently developed for the IPB D-1 chicken, a hybrid composed of 75% local and 25% broiler genetics. Optimizing growth necessitates careful adjustment of protein intake throughout the rearing period. This study examined the effects of two protein levels (20% and 18%) on unsexed, day-old IPB D-1 chickens. Two hundred chicks were allocated into four treatment groups, each with diets containing either 20% or 18% protein, with or without dragon fruit peel extract supplementation. Performance indicators such as body weight gain, feed intake, feed conversion ratio (FCR), and mortality were measured. Results indicated that chickens fed a 20% protein diet supplemented with dragon fruit peel extract exhibited significantly enhanced weight gain, improved FCR, and lower mortality rates (P < 0.05). These findings suggest that optimizing protein content with natural additives like dragon fruit peel extract may enhance growth performance during the starter phase for hybrid broiler chickens.

Background and Aim: The development of zinc-based antimicrobials has progressed from conventional to nanoparticle (NP) formulations due to their enhanced biological properties. This study evaluates the antibacterial efficacy of green-synthesized zinc oxide NPs (ZnO-NPs) derived from Garcinia mangostana leaf extract against both pathogenic and non-pathogenic bacteria relevant to poultry health. Materials and Methods: Using a completely randomized design, six treatment groups were tested: Positive control (PC) (tetracycline, 2.5 mg/mL), negative control (NC) (HCl 0.1 N + distilled water), and ZnO-NPs at concentrations of 2.5, 5, 7.5, and 10 mg/mL. The antimicrobial activity was assessed using the agar well diffusion method, measuring inhibition zones against Escherichia coli, S. Typhimurium, Staphylococcus aureus, and Lactobacillus plantarum. Results: The positive control demonstrated the most significant inhibition zones across all bacterial strains. ZnO-NPs exhibited dose-dependent antibacterial activity, with maximum inhibition zones recorded as 18.58 mm for E. coli, 17.09 mm for S. Typhimurium, and 17.41 mm for S. aureus at the highest concentration (10 mg/mL). However, the antibacterial activity against L. plantarum was less pronounced, with a maximum inhibition zone of 9.93 mm. These findings indicate selective toxicity of ZnO-NPs, favoring pathogenic over non-pathogenic strains. Conclusion: Green-synthesized ZnO-NPs using G. mangostana leaf extract demonstrate promising antibacterial properties against poultry pathogens. Their selective action highlights potential applications as eco-friendly feed additives to improve poultry health and mitigate pathogenic risks.

OBJECTIVE:This meta-analysis aims to examine the efficacy of essential oils (EO) as an anticoccidial alternative on broiler chickens under coccidia challenged trials, focusing on performance indicators including average daily gain (ADG), feed intake (FI), feed conversion ratio (FCR), final body weight (BW), mortality, and intestinal lesion. METHODS:A random-effects model was performed using the metafor package in R software. In a subgroup meta-analysis, treatment groups including coccidia-infected birds [C+], C+ group treated with EO [C+EO] or antibiotics [C+AB], and a non-infected control group treated with EO or AB, were compared against the control group [CON]. RESULTS:As expected, C+ birds had lower (p<0.001) final BW and ADG as well as higher (p<0.001) FCR. Administration of either EO or AB on birds with coccidiosis infection resulted in similar final BW, ADG, FI, and FCR with CON birds, suggesting the comparable effectiveness of EO and AB to alleviate the adverse effects of coccidiosis. Broilers on the C+ group exhibited increased small intestine damage as shown by the greater (p<0.001) lesion score, but the mortality was not different from CON and other treatment groups. The Eimeria oocyst count was lower on birds treated with EO than on the infected birds, with an average suppression of 42.11%. Meta-regression demonstrated that C+ birds had inferior FI and ADG than CON and C+EO birds. However, high heterogeneity between studies was identified in all measured outcomes as shown by I2>75%, suggesting wide variability among study conditions. CONCLUSION:EO may serve as an alternative antibiotic to mitigate the negative impacts of coccidiosis infection in broiler chickens.

Introduction:Raising broiler chickens in tropical countries faces challenges, primarily heat stress, which reduces feed intake, weakens immunity, increases infections and mortality, and impairs growth, ultimately leading to economic losses. This study evaluated the effect of dietary lemongrass oil and selenium on broiler production performance and internal organ weight. Materials & Methods:A total of 288 Cobb strain broilers were allocated into 6 treatments with 6 replicates, using a completely randomized factorial design. Treatment included lemongrass oil (0 mL/kg, 2 mL/kg, 4 mL/kg) and selenomethionine (0 ppm, 0.4 ppm). Parameters measured were broiler production performances, internal organs, and immune organ weights. Results:The inclusion of 4 mL/kg lemongrass oil significantly reduced (P<0.05) feed intake, body weight, and body weight gain. The inclusion of 0.4 ppm selenomethionine significantly increased (P<0.05) the body weight and reduced the FCR of broiler chickens. The inclusion of 4 mL/kg lemongrass oil significantly reduced (P<0.05) the feed intake, body weight gain, and body weight, while significantly increasing (P<0.05) proventriculus weight. The combination of 4 mL/ kg lemongrass oil and 0.4 ppm selenomethionine significantly reduced (P<0.05) the weights of the ileum and gallbladder. The treatment did not affect (P>0.05) the weight of the ventriculus, heart, liver, duodenum, jejunum, cecum, colon, abdominal fat, thymus, lymph, and bursa of Fabricius. Conclusion:The conclusion is that the inclusion of 0.4 ppm selenomethionine in the diet increases the body weight and feed efficiency, whereas inclusion of up to 4 mL/kg lemongrass oil in the diet reduces the broiler's production performances and the weight of the ileum and gallbladder.

The management of microbial infections in poultry farming continues to be largely antibiotic-dependent. Despite this, the application of Antibiotic Growth Promoters (AGPs) in poultry feed has been banned, necessitating the use of herbal feed additives such as Brotowali (Tinospora crispa). This study aimed to evaluate the effects of Brotowali stem meal on the performance and immune organs of hybrid ducks. A total of 200 hybrid ducks Gunsi 888 were used in this study, reared from 11 to 46 days of age. The ducks were fed either a basal diet as a control (P1) or a basal diet supplemented with 0.5% Brotowali stem meal (P2), 1% (P3), and 1.5% (P4). The observed immune organs included the thymus, bursa of Fabricius, and spleen. The study was conducted in Bogor, West Java, while the an analysis of Brotowali’s phytochemical properties was conducted at the Tropical Biopharmaca Research Center of IPB University. All collected data were analyzed using analysis of variance (ANOVA), and significant differences were further analyzed using Duncan’s Multiple Range Test (DMRT) with SPSS version 25. The results showed that Brotowali stem meal had no significant effect (P>0.05) on the immunity of hybrid ducks. However, Brotowali stem meal significantly (P<0.05) improved the performance of hybrid ducks, as evidenced by increased body weight and decreased feed conversion ratios. In conclusion, Brotowali can enhance the performance of hybrid ducks, and it does not affect the stress levels of the livestock.

This research sought to explore how different processing methods, including soaking and peeling the beans, and the introduction of protease enzyme and non-starch polysaccharides (NSP) enzymes, impact the nutrient content, metabolizable energy, and protein digestibility of processed Jack bean meal. The study utilized a completely randomized design, with four treatments and four replications. A total of 36 animals were involved, with 32 used for measuring metabolizable energy and protein digestibility, and 4 broiler chickens for endogenous measurement. Treatments included processed Jack bean meal alone, with protease enzyme, with NSP enzymes, and with both enzymes combined. Results showed a significant increase (P<0.05) in metabolizable energy and protein digestibility with enzyme supplementation. This improvement was attributed to the protease enzyme breaking down proteins into smaller peptides and NSP enzymes facilitating the breakdown of non-starch polysaccharides, enhancing digestion and absorption. In conclusion, supplementing peeled Jack bean meal with protease and NSP enzymes enhances its metabolizable energy and protein digestibility, suggesting its potential as an alternative protein source for broiler chickens.

Abstract Canavalia ensiformis L. (jackbean) meal shows potential as an ingredient for poultry feed protein source, providing essential nutrients for poultry growth while reducing dependence on soybean meal. However, the incorporation of jackbean meal in poultry rations is limited due to a need for comprehensive information on factors such as nutritional and anti-nutritional content, digestibility, and nutrient utilization. This experiment is designed to contribute valuable insights into the potential of jackbean meal as an alternative protein source for poultry feed by assessing its physicochemical value, metabolizable energy, and protein digestibility. The study assessed the crude levels of protein, fiber, ash, and ether extract, as well as the presence of HCN. Additionally, it evaluated the bulk and tapped density of peeled and unpeeled jackbean meal compared to soybean meal. Metabolizable energy and protein digestibility were also assessed. The acquired data underwent analysis through analysis of variance and Tukey test when significances were found. The results of the experiment indicated that the physicochemical quality, metabolizable energy, and protein digestibility of the peeled and unpeeled jack bean meal was comparable to that of soybean meal. In addition, the peeled revealed better results compared to the unpeeled jackbean meal.

High-productivity laying poultry during the production period may experience bone problems, as structural medullary bone is progressively absorbed to supply calcium for eggshell formation. This study aims to evaluate the usage of different particle sizes of limestone (fine (0,025mm), and coarse (1mm)), and split feeding system (morning (8 am) and afternoon (15 pm)) on laying quail productivity. This research used 160 quail aged 18 weeks, which is reared up to 23 weeks. A complete randomized design (CRD) with 4 treatments and 4 replicates was used in this study. Each replicate consisted of 10 quails. The cages used were multilevel colonies equipped with feed and drink containers. The diet treatments were: P0= diet contained fine (FL) and coarse (CL) limestone at a (25:25): (25:25) ratio fed in the morning and afternoon, P1= diet contained 75FL-(Morning): 25CL-(Afternoon), P2= diet contained 50FL-(Morning):50CL-(Afternoon) and P3= diet contained 25FL-(Morning):75CL-(Afternoon). Data were analyzed using ANOVA and further analyzed using the Duncan test. The results showed that the ration treatment with limestone divided into fine and coarse forms with split feeding in the morning and evening significantly increased (p<0.05) tibia bone Ca and P content but decreased (p<0.05) feed conversion. However, it increased (p<0.05) quail egg index value. Feeding calcium at a ratio of 25% (morning) and 75% (afternoon) resulted in the highest ration utilization efficiency, Ca and P deposits in the tibia bone, and increased egg index values. Key words: Ca and P medullary bone, calcium effectivity, eggs quality, performance, quail laying