Prospects of Poikelocercus pictus (Orthoptera: Acrididae) as an alternative protein source for Rhode Island Red chicken

2.1 Birds and their management

Rhode Island Red (RIR) chickens were obtained from the hatchery of the Poultry Research Institute (PRI), Rawalpindi and were maintained at Government Poultry Farm, Sook Kalan, Gujrat, Punjab, Pakistan. Chickens were put in pens randomly with a density of eight birds per pen (≈3ft²/chick). The pens were having a perch assembly (50 cm from the floor) made up of wood (Khawaja et al., 2012a,b; 2013a,b).

Chicks were maintained under recommended conditions of temperature (34 ± 01 °C) during 1st week and then, we lowered the temperature to 3 °C/week. The pens were provided with at least nine hours of light per day (maximum 14 h). Feed and water provision was ad libitum consumption and chicken vaccination program was followed as per guidelines for the breed and area (Khawaja et al., 2013a,b).

2.2 Collection of Grasshoppers

Adult grasshoppers were collected from pesticide-free fields selected by personal interview survey of the community of Deva Vatala National Park (DVNP), Bhimber. Only those sites were selected which have a history of no pesticide usage for at least the last five years. Specimens were identified by using standard taxonomic keys for the Acridids (Bughio et al., 2014; Gupta and Chandra, 2016).

Grasshoppers were deprived of food for 24 h before killing and processing. Wings and legs were removed and the bodies were dried under a hot air oven at 40 °C. Then, the dried grasshoppers were milled for feed formulation.

2.3 Composition of feed

The standard commercial feed ingredients were obtained from Ahsan Feed Mills, Tiwana Wala Pea, Gujranwala, Punjab and feed were prepared (Table 1) by following the National Research Council’s recommendations (Council, 1994).

2.4 Experimental design

The experiment was laid out in a Completely Randomized Design (CRD) with six replications. A day-old 192 unsexed chickens were then randomly divided into four groups based on feed treatment: T₀ (control group: fed on a commercial diet throughout the trial), T₁ (PP diet throughout the trial (45 days), T₂ (PP diet for last 30 days of trial), and T₃ (PP diet for last 15 days).

2.5 Estimation of feeds ingredients

For proximate analysis of experimental feeds, 50 g/Kg of diet from each treatment was collected and replicated thrice. Crude lipid (using Soxhlet apparatus), crude protein (using Kjeldahl method), and ash content (using the muffle furnace at 550 ± 50 °C for about 6 h) were determined (Horwitz, 2010; Kim et al., 2017). Before protein estimation by spectrophotometry, the samples were kept at room temperature for at least half an hour. The absorbance of samples was measured at 595 nm. Carbohydrate content was calculated by difference method (100 − sum of protein, fat, and ash). Nitrogen-free extract (NFE) was calculated by subtracting the sum of crude protein, fat, ash and fibre from 100. Moisture content was determined by heat drying of the samples at 105 °C for 4 h.

2.6 Growth performance

Growth performance was measured by feed intake and weight gain. We weighed chickens before the start of experiment and then on the 15th, 30th, and 45th days. Weight of chicks was recorded after 12 h fasting and feed conversion ratio (FCR) was determined by formula: $$\mathrm{F}\mathrm{C}\mathrm{R}=\mathrm{T}\mathrm{o}\mathrm{t}\mathrm{a}\mathrm{l}\mathrm{f}\mathrm{e}\mathrm{e}\mathrm{d}\mathrm{i}\mathrm{n}\mathrm{t}\mathrm{a}\mathrm{k}\mathrm{e}/\mathrm{t}\mathrm{o}\mathrm{t}\mathrm{a}\mathrm{l}\mathrm{w}\mathrm{e}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}\mathrm{g}\mathrm{a}\mathrm{i}\mathrm{n}$$

2.7 Hematological and biochemical analysis

In the morning before feeding, we collected blood samples from the wing veins of chicks at the end of the 15th, 30th, and 45th day. Six samples of blood were taken from each group. cholesterol, protein, calcium, glucose, triglyceride, alkaline phosphatase, and uric acid were analyzed. A 5 ml blood sample in centrifuge tubes having heparin was centrifuged at 3000 rpm for 15 min. Serum samples were stored at −20 °C till further chemical analysis. Complete blood count (Hb, WBCs, RBCs, MCV, HCT, MCH, MCHC, and Platelets) was analyzed with an automated Hematology Analyzer (model HKTE0112 Guangzhou Hekang, China).

Commercial kits and diagnostic examinations were used to measure the biochemical characteristics of blood calorimetrically on a UV–visible spectrophotometer. Total protein was detected and quantified using the colorimetric method. Glucose and total cholesterol concentration were quantitatively measured with the help of the enzymatic colorimetric method.

2.8 Meat analysis

Chicks were slaughtered on 45th day to collect meat from breasts and thighs which was then dried, and ground for analysis i.e., crude protein, dry matter, moisture percentage, fat content, and total ash.

2.9 Statistical analysis

Analysis of variance (ANOVA) was performed to determine the significance level and means were compared by applying Tukey’s post hoc test where effects were significant (P < 0.05) Statistix Software.

3.1 Feed analysis

The estimation of feed compositions showed crude protein content of PP (65.92 ± 0.75%) was higher as compared to commercial diet (55.20 ± 0.75%). However, crude lipid content (09.75 ± 0.52) and ash (15.39 ± 0.52) were higher in commercial diet (Table 1).

3.2 Growth performance of RIR chicken

In this study, we assessed the growth performance of RIR chickens by feeding them PP diet diets for two, four and six weeks in comparison with commercial feed (control) using feed intake, body weight gain, and FCR (Table 2).

3.3 Feed intake (g)

Chicken showed significantly greater feed intake when fed on PP diet as compared to commercial feed (P < 0.05). RIR chicken fed on PP diet for six weeks consumed significantly more feed (P < 0.05) as compared to commercial diet (Table 2). After 15 days, maximum feed intake was recorded in PP diet (547.18 ± 7.28) as compared to other treatments. Similarly, maximum feed intake was observed PP diet after 30 days (696.64 ± 4.56) and 45 days (793.33 ± 5.45) (Table 2).

3.4 Weight gain (g)

The average weight gain by Rhode Island Red chicks after two, four and six weeks showed significant variations (P < 0.05). We recorded that, after 15 days, RIR chicken fed with PP diet gained an average body weight of 195.25 ± 3.72 g. Similarly, after 30 days, significantly higher weight gain was recorded in chicken fed on PP diet (T₁) 216.85 ± 4.21 g as compared with control (193.33 ± 3.76). The lowest body weight gain was observed in control (Table 2).

3.5 Feed conversion ratio (FCR)

RIR chicken showed significant differences in FCR between all treatment groups (P < 0.05). The highest FCR was recorded in chicken fed on PP diet (T₁) after 15 days (2.80 ± 0.01), 30 days (3.17 ± 0.03) and 45 days (3.21 ± 0.03). We observed that FCR was higher in chickens after six weeks as compared to four weeks and two weeks (Table 2).

3.6 Meat analysis

Data on meat analysis of RIR Chicks showed significant differences (P < 0.05) in dry matter, crude protein, and crude fat (Table 3). In breasts, we observed that RIR chickens showed better performance when fed on PP diet as compared to control. Crude fat also showed significant variations in means between treatments. Maximum crude fat was recovered when chicks were fed PP diet for six weeks (T₁). Similarly, crude protein was significantly different among treatments.

In thigh meat, we observed significant differences in crude protein and cure fat content (P < 0.05). Significantly higher means were recorded in T₁ as compared to other PP diets and control. Ash content showed non-significant differences in means in both type of meat i.e., breast and thighs.

3.7 Hematological analysis

Data showed non-significant variations (P > 0.05) in hematological parameters i.e., HCT (%), Haemoglobin (g/dL), MCH (%), MCHC %, Platelets (×10³/µL), RBC (×10⁶/µL), and WBC (×103/µL) among four treatments (Table 4).

3.8 Biochemical analysis

Results demonstrated that Cholesterol (mg/dL), Glucose (mg/dL), Triglyceride (mg/dL), Alkaline Phosphate (U/L), Protein (g/dL), Uric Acid (mg/dL), and Calcium (mg/dL) indicated non-significant differences (P > 0.05) (Table 5). Calcium and cholesterol levels in the blood serum of RIR chicks showed non-significant differences (P > 0.05).